1
|
Said AA, Aydin E, Ugur E, Xu Z, Deger C, Vishal B, Vlk A, Dally P, Yildirim BK, Azmi R, Liu J, Jackson EA, Johnson HM, Gui M, Richter H, Pininti AR, Bristow H, Babics M, Razzaq A, Allen TG, Ledinský M, Yavuz I, Rand BP, De Wolf S. Sublimed C 60 for efficient and repeatable perovskite-based solar cells. Nat Commun 2024; 15:708. [PMID: 38267408 PMCID: PMC10808237 DOI: 10.1038/s41467-024-44974-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 01/08/2024] [Indexed: 01/26/2024] Open
Abstract
Thermally evaporated C60 is a near-ubiquitous electron transport layer in state-of-the-art p-i-n perovskite-based solar cells. As perovskite photovoltaic technologies are moving toward industrialization, batch-to-batch reproducibility of device performances becomes crucial. Here, we show that commercial as-received (99.75% pure) C60 source materials may coalesce during repeated thermal evaporation processes, jeopardizing such reproducibility. We find that the coalescence is due to oxygen present in the initial source powder and leads to the formation of deep states within the perovskite bandgap, resulting in a systematic decrease in solar cell performance. However, further purification (through sublimation) of the C60 to 99.95% before evaporation is found to hinder coalescence, with the associated solar cell performances being fully reproducible after repeated processing. We verify the universality of this behavior on perovskite/silicon tandem solar cells by demonstrating their open-circuit voltages and fill factors to remain at 1950 mV and 81% respectively, over eight repeated processes using the same sublimed C60 source material. Notably, one of these cells achieved a certified power conversion efficiency of 30.9%. These findings provide insights crucial for the advancement of perovskite photovoltaic technologies towards scaled production with high process yield.
Collapse
Affiliation(s)
- Ahmed A Said
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
| | - Erkan Aydin
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
| | - Esma Ugur
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Zhaojian Xu
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Caner Deger
- Department of Physics, Marmara University, Istanbul, Türkiye
| | - Badri Vishal
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Aleš Vlk
- Laboratory of Nanostructures and Nanomaterials, Institute of Physics, Academy of Sciences of the Czech Republic, v. v. i., Cukrovarnická 10, Prague, 162 00, Czech Republic
| | - Pia Dally
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Bumin K Yildirim
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Randi Azmi
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Jiang Liu
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | | | - Holly M Johnson
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Manting Gui
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | | | - Anil R Pininti
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Helen Bristow
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Maxime Babics
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Arsalan Razzaq
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Thomas G Allen
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Martin Ledinský
- Laboratory of Nanostructures and Nanomaterials, Institute of Physics, Academy of Sciences of the Czech Republic, v. v. i., Cukrovarnická 10, Prague, 162 00, Czech Republic
| | - Ilhan Yavuz
- Department of Physics, Marmara University, Istanbul, Türkiye
| | - Barry P Rand
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Stefaan De Wolf
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
| |
Collapse
|
2
|
Zarei M, Loy JC, Li M, Zhou Z, Sinha S, LeMieux M, Walker SB, Rand BP, Leu PW. Substrate-embedded metal meshes for ITO-free organic light emitting diodes. Opt Express 2023; 31:34697-34707. [PMID: 37859220 DOI: 10.1364/oe.499932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/01/2023] [Indexed: 10/21/2023]
Abstract
Organic light-emitting diodes (OLEDs) have great potential for use in large-area display and lighting applications, but their widespread adoption for large areas is hindered by the high cost and insufficient performance of indium tin oxide (ITO) anodes. In this study, we introduce an alternative anode material - a silver mesh embedded in glass - to facilitate production of large-area OLEDs. We present a facile, scalable manufacturing technique to create high aspect ratio micromeshes embedded in glass to provide the planar geometry needed for OLED layers. Our phosphorescent green OLEDs achieve a current efficiency of 51.4 cd/A at 1000 cd/m2 and reach a slightly higher external quantum efficiency compared to a standard ITO/glass reference sample. Notably, these advancements are achieved without any impact on the viewing angle of the OLEDs. These findings represent a promising advancement towards ITO-free, high-efficiency OLEDs for various high performance, large-area applications, such as lighting and displays.
Collapse
|
3
|
Hu J, Xu Z, Murrey TL, Pelczer I, Kahn A, Schwartz J, Rand BP. Triiodide Attacks the Organic Cation in Hybrid Lead Halide Perovskites: Mechanism and Suppression. Adv Mater 2023; 35:e2303373. [PMID: 37363828 DOI: 10.1002/adma.202303373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/08/2023] [Indexed: 06/28/2023]
Abstract
Molecular I2 can be produced from iodide-based lead perovskites under thermal stress; triiodide, I3 - , is formed from this I2 and I- . Triiodide attacks protic cation MA+ - or FA+ -based lead halide perovskites (MA+ , methylammonium; FA+ , formamidinium) as explicated through solution-based nuclear magnetic resonance (NMR) studies: triiodide has strong hydrogen-bonding affinity for MA+ or FA+ , which leads to their deprotonation and perovskite decomposition. Triiodide is a catalyst for this decomposition that can be obviated through perovskite surface treatment with thiol reducing agents. In contrast to methods using thiol incorporation into perovskite precursor solutions, no penetration of the thiol into the bulk perovskite is observed, yet its surface application stabilizes the perovskite against triiodide-mediated thermal stress. Thiol applied to the interface between FAPbI3 and Spiro-OMeTAD ("Spiro") prevents oxidized iodine species penetration into Spiro and thus preserves its hole-transport efficacy. Surface-applied thiol affects the perovskite work function; it ameliorates hole injection into the Spiro overlayer, thus improving device performance. It helps to increase interfacial adhesion ("wetting"): fewer voids are observed at the Spiro/perovskite interface if thiols are applied. Perovskite solar cells (PSCs) incorporating interfacial thiol treatment maintain over 80% of their initial power conversion efficiency (PCE) after 300 h of 85 °C thermal stress.
Collapse
Affiliation(s)
- Junnan Hu
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Zhaojian Xu
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Tucker L Murrey
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - István Pelczer
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Antoine Kahn
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Jeffrey Schwartz
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Barry P Rand
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| |
Collapse
|
4
|
Dull JT, He X, Viereck J, Ai Q, Ramprasad R, Otani MC, Sorli J, Brandt JW, Carrow BP, Tinoco AD, Loo YL, Risko C, Rangan S, Kahn A, Rand BP. Thin-Film Organic Heteroepitaxy. Adv Mater 2023; 35:e2302871. [PMID: 37394983 DOI: 10.1002/adma.202302871] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 06/16/2023] [Indexed: 07/04/2023]
Abstract
Incorporating crystalline organic semiconductors into electronic devices requires understanding of heteroepitaxy given the ubiquity of heterojunctions in these devices. However, while rules for commensurate epitaxy of covalent or ionic inorganic material systems are known to be dictated by lattice matching constraints, rules for heteroepitaxy of molecular systems are still being written. Here, it is found that lattice matching alone is insufficient to achieve heteroepitaxy in molecular systems, owing to weak intermolecular forces that describe molecular crystals. It is found that, in addition, the lattice matched plane also must be the lowest energy surface of the adcrystal to achieve one-to-one commensurate molecular heteroepitaxy over a large area. Ultraviolet photoelectron spectroscopy demonstrates the lattice matched interface to be of higher electronic quality than a disordered interface of the same materials.
Collapse
Affiliation(s)
- Jordan T Dull
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Xu He
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Jonathan Viereck
- Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, Piscataway, NJ, 08854, USA
| | - Qianxiang Ai
- Department of Chemistry and Center for Applied Energy Research, University of Kentucky, Lexington, KY, 40506, USA
| | - Ritika Ramprasad
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Maria Clara Otani
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Jeni Sorli
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Jason W Brandt
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Brad P Carrow
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Arthur D Tinoco
- Department of Chemistry, University of Puerto Rico-Río Piedras Campus, San Juan, PR, 00925, USA
| | - Yueh-Lin Loo
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Chad Risko
- Department of Chemistry and Center for Applied Energy Research, University of Kentucky, Lexington, KY, 40506, USA
| | - Sylvie Rangan
- Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers University, Piscataway, NJ, 08854, USA
| | - Antoine Kahn
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Barry P Rand
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| |
Collapse
|
5
|
Gunnarsson WB, Roh K, Zhao L, Murphy JP, Grede AJ, Giebink NC, Rand BP. Toward Nonepitaxial Laser Diodes. Chem Rev 2023. [PMID: 37219995 DOI: 10.1021/acs.chemrev.2c00721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Thin-film organic, colloidal quantum dot, and metal halide perovskite semiconductors are all being pursued in the quest for a wavelength-tunable diode laser technology that does not require epitaxial growth on a traditional semiconductor substrate. Despite promising demonstrations of efficient light-emitting diodes and low-threshold optically pumped lasing in each case, there are still fundamental and practical barriers that must be overcome to reliably achieve injection lasing. This review outlines the historical development and recent advances of each material system on the path to a diode laser. Common challenges in resonator design, electrical injection, and heat dissipation are highlighted, as well as the different optical gain physics that make each system unique. The evidence to date suggests that continued progress for organic and colloidal quantum dot laser diodes will likely hinge on the development of new materials or indirect pumping schemes, while improvements in device architecture and film processing are most critical for perovskite lasers. In all cases, systematic progress will require methods that can quantify how close new devices get with respect to their electrical lasing thresholds. We conclude by discussing the current status of nonepitaxial laser diodes in the historical context of their epitaxial counterparts, which suggests that there is reason to be optimistic for the future.
Collapse
Affiliation(s)
- William B Gunnarsson
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Kwangdong Roh
- Department of Physics, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Lianfeng Zhao
- Holcombe Department of Electrical and Computer Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - John P Murphy
- Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Alex J Grede
- Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Noel C Giebink
- Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Barry P Rand
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
6
|
Zhao L, Astridge DD, Gunnarsson WB, Xu Z, Hong J, Scott J, Kacmoli S, Al Kurdi K, Barlow S, Marder SR, Gmachl CF, Sellinger A, Rand BP. Thermal Properties of Polymer Hole-Transport Layers Influence the Efficiency Roll-off and Stability of Perovskite Light-Emitting Diodes. Nano Lett 2023. [PMID: 37220025 DOI: 10.1021/acs.nanolett.3c00148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
While the performance of metal halide perovskite light-emitting diodes (PeLEDs) has rapidly improved in recent years, their stability remains a bottleneck to commercial realization. Here, we show that the thermal stability of polymer hole-transport layers (HTLs) used in PeLEDs represents an important factor influencing the external quantum efficiency (EQE) roll-off and device lifetime. We demonstrate a reduced EQE roll-off, a higher breakdown current density of approximately 6 A cm-2, a maximum radiance of 760 W sr-1 m-2, and a longer device lifetime for PeLEDs using polymer HTLs with high glass-transition temperatures. Furthermore, for devices driven by nanosecond electrical pulses, a record high radiance of 1.23 MW sr-1 m-2 and an EQE of approximately 1.92% at 14.6 kA cm-2 are achieved. Thermally stable polymer HTLs enable stable operation of PeLEDs that can sustain more than 11.7 million electrical pulses at 1 kA cm-2 before device failure.
Collapse
Affiliation(s)
- Lianfeng Zhao
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Holcombe Department of Electrical and Computer Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Daniel D Astridge
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - William B Gunnarsson
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Zhaojian Xu
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Jisu Hong
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Jonathan Scott
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Sara Kacmoli
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Khaled Al Kurdi
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Stephen Barlow
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Seth R Marder
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80303, United States
- Department of Chemical and Biological Engineering, Department of Chemistry, and Materials Science and Engineering Program, University of Colorado Boulder, Boulder, Colorado 80303, United States
| | - Claire F Gmachl
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Alan Sellinger
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
- Materials Science Program, Colorado School of Mines, Golden, Colorado 80401, United States
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Barry P Rand
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
7
|
Xu Z, Astridge DD, Kerner RA, Zhong X, Hu J, Hong J, Wisch JA, Zhu K, Berry JJ, Kahn A, Sellinger A, Rand BP. Origins of Photoluminescence Instabilities at Halide Perovskite/Organic Hole Transport Layer Interfaces. J Am Chem Soc 2023; 145:11846-11858. [PMID: 37202123 DOI: 10.1021/jacs.3c03539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Metal halide perovskites are promising for optoelectronic device applications; however, their poor stability under solar illumination remains a primary concern. While the intrinsic photostability of isolated neat perovskite samples has been widely discussed, it is important to explore how charge transport layers─employed in most devices─impact photostability. Herein, we study the effect of organic hole transport layers (HTLs) on light-induced halide segregation and photoluminescence (PL) quenching at perovskite/organic HTL interfaces. By employing a series of organic HTLs, we demonstrate that the HTL's highest occupied molecular orbital energy dictates behavior; furthermore, we reveal the key role of halogen loss from the perovskite and subsequent permeation into organic HTLs, where it acts as a PL quencher at the interface and introduces additional mass transport pathways to facilitate halide phase separation. In doing so, we both reveal the microscopic mechanism of non-radiative recombination at perovskite/organic HTL interfaces and detail the chemical rationale for closely matching the perovskite/organic HTL energetics to maximize solar cell efficiency and stability.
Collapse
Affiliation(s)
- Zhaojian Xu
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Daniel D Astridge
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Ross A Kerner
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Xinjue Zhong
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Junnan Hu
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Jisu Hong
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Jesse A Wisch
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Kai Zhu
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Joseph J Berry
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Antoine Kahn
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Alan Sellinger
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Barry P Rand
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
8
|
Kerner RA, Cohen AV, Xu Z, Kirmani AR, Park SY, Harvey SP, Murphy JP, Cawthorn RC, Giebink NC, Luther JM, Zhu K, Berry JJ, Kronik L, Rand BP. Electrochemical Doping of Halide Perovskites by Noble Metal Interstitial Cations. Adv Mater 2023:e2302206. [PMID: 37052234 DOI: 10.1002/adma.202302206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 03/29/2023] [Indexed: 06/04/2023]
Abstract
Metal halide perovskites are an attractive class of semiconductors, but it has proven difficult to control their electronic doping by conventional strategies due to screening and compensation by mobile ions or ionic defects. Noble-metal interstitials represent an under-studied class of extrinsic defects that plausibly influence many perovskite-based devices. In this work, doping of metal halide perovskites is studied by electrochemically formed Au+ interstitial ions, combining experimental data on devices with a computational analysis of Au+ interstitial defects based on density functional theory (DFT). Analysis suggests that Au+ cations can be easily formed and migrate through the perovskite bulk via the same sites as iodine interstitials (Ii + ). However, whereas Ii + compensates n-type doping by electron capture, the noble-metal interstitials act as quasi-stable n-dopants. Experimentally, voltage-dependent, dynamic doping by current density-time (J-t), electrochemical impedance, and photoluminescence measurements are characterized. These results provide deeper insight into the potential beneficial and detrimental impacts of metal electrode reactions on long-term performance of perovskite photovoltaic and light-emitting diodes, as well as offer an alternative doping explanation for the valence switching mechanism of halide-perovskite-based neuromorphic and memristive devices.
Collapse
Affiliation(s)
- Ross A Kerner
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Ayala V Cohen
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovoth, 76100, Israel
| | - Zhaojian Xu
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Ahmad R Kirmani
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - So Yeon Park
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Steven P Harvey
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - John P Murphy
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Robert C Cawthorn
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Noel C Giebink
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Joseph M Luther
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Kai Zhu
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Joseph J Berry
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
- Department of Physics, University of Colorado Boulder, Boulder, CO, 80309, USA
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Leeor Kronik
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovoth, 76100, Israel
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| |
Collapse
|
9
|
Dull JT, Chen X, Johnson HM, Otani MC, Schreiber F, Clancy P, Rand BP. A comprehensive picture of roughness evolution in organic crystalline growth: the role of molecular aspect ratio. Mater Horiz 2022; 9:2752-2761. [PMID: 36069252 DOI: 10.1039/d2mh00854h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Exploiting the capabilities of organic semiconductors for applications ranging from light-emitting diodes to photovoltaics to lasers relies on the creation of ordered, smooth layers for optimal charge carrier mobilities and exciton diffusion. This, in turn, creates a demand for organic small molecules that can form smooth thin film crystals via homoepitaxy. We have studied a set of small-molecule organic semiconductors that serve as templates for homoepitaxy. The surface roughness of these materials is measured as a function of adlayer film thickness from which the growth exponent (β) is extracted. Notably, we find that three-dimensional molecules that have low molecular aspect ratios (AR) tend to remain smooth as thickness increases (small β). This is in contrast to planar or rod-like molecules with high AR that quickly roughen (large β). Molecular dynamics simulations find that the Ehrlich-Schwöbel barrier (EES) alone is unable to fully explain this trend. We further investigated the mobility of ad-molecules on the crystalline surface to categorize their diffusion behaviors and the effects of aggregation to account for the different degrees of roughness that we observed. Our results suggest that low AR molecules have low molecular mobility and moderate EES which creates a downward funneling effect leading to smooth crystal growth.
Collapse
Affiliation(s)
- Jordan T Dull
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA.
| | - Xiangyu Chen
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
| | - Holly M Johnson
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA.
| | - Maria Clara Otani
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA.
| | - Frank Schreiber
- Institute for Applied Physics, University of Tubingen, 72076 Tubingen, Germany
| | - Paulette Clancy
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA.
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ 08544, USA
| |
Collapse
|
10
|
Min H, Hu J, Xu Z, Liu T, Khan SUZ, Roh K, Loo YL, Rand BP. Hot-Casting-Assisted Liquid Additive Engineering for Efficient and Stable Perovskite Solar Cells. Adv Mater 2022; 34:e2205309. [PMID: 35841176 DOI: 10.1002/adma.202205309] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 07/12/2022] [Indexed: 06/15/2023]
Abstract
High-performance inorganic-organic lead halide perovskite solar cells (PSCs) are often fabricated with a liquid additive such as dimethyl sulfoxide (DMSO), which retards crystallization and reduces roughness and pinholes in the perovskite layers. However, DMSO can be trapped during perovskite film formation and induce voids and undesired reaction byproducts upon later processing steps. Here, it is shown that the amount of residual DMSO can be reduced in as-spin-coated films significantly through use of preheated substrates, or a so-called hot-casting method. Hot casting increases the perovskite film thickness given the same concentration of solutions, which allows for reducing the perovskite solution concentration. By reducing the amount of DMSO in proportion to the concentration of perovskite precursors and using hot casting, it is possible to fabricate perovskite layers with improved perovskite-substrate interfaces by suppressing the formation of byproducts, which increase trap density and accelerate degradation of the perovskite layers. The best-performing PSCs exhibit a power conversion efficiency (PCE) of 23.4% (23.0% stabilized efficiency) under simulated solar illumination. Furthermore, encapsulated devices show considerably reduced post-burn-in decay, retaining 75% and 90% of their initial and post-burn-in efficiencies after 3000 h of operation with maximum power point tracking (MPPT) under high power of ultraviolet (UV)-containing continuous light exposure.
Collapse
Affiliation(s)
- Hanul Min
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
- Princeton Institute for International and Regional Studies, Princeton University, Princeton, NJ, 08544, USA
| | - Junnan Hu
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Zhaojian Xu
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Tianran Liu
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Saeed-Uz-Zaman Khan
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Kwangdong Roh
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Yueh-Lin Loo
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Barry P Rand
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| |
Collapse
|
11
|
Gunnarsson WB, Xu Z, Noel NK, Rand BP. Improved Charge Balance in Green Perovskite Light-Emitting Diodes with Atomic-Layer-Deposited Al 2O 3. ACS Appl Mater Interfaces 2022; 14:34247-34252. [PMID: 35353475 DOI: 10.1021/acsami.2c00860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Perovskite light-emitting diodes (LEDs) have experienced a rapid increase in efficiency over the last several years and are now regarded as promising low-cost devices for displays and communication systems. However, it is often challenging to employ ZnO, a well-studied electron transport material, in perovskite LEDs due to chemical instability at the ZnO/perovskite interface and charge injection imbalance caused by the relatively high conductivity of ZnO. In this work, we address these problems by depositing an ultrathin Al2O3 interlayer at the ZnO/perovskite interface, allowing the fabrication of green-emitting perovskite LEDs with a maximum luminance of 21 815 cd/m2. Using atomic layer deposition, we can precisely control the Al2O3 thickness and thus fine-tune the electron injection from ZnO, allowing us to enhance the efficiency and operational stability of our LEDs.
Collapse
Affiliation(s)
- William B Gunnarsson
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Zhaojian Xu
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Nakita K Noel
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, United States
| | - Barry P Rand
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
12
|
Eatmon Y, Romiluyi O, Ganley C, Ni R, Pelczer I, Clancy P, Rand BP, Schwartz J. Untying the Cesium "Not": Cesium-Iodoplumbate Complexation in Perovskite Solution-Processing Inks Has Implications for Crystallization. J Phys Chem Lett 2022; 13:6130-6137. [PMID: 35759533 DOI: 10.1021/acs.jpclett.2c01344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We illustrate the critical importance of the energetics of cation-solvent versus cation-iodoplumbate interactions in determining the stability of ABX3 perovskite precursors in a dimethylformamide (DMF) solvent medium. We have shown, through a complementary suite of nuclear magnetic resonance (NMR) and computational studies, that Cs+ exhibits significantly different solvent vs iodoplumbate interactions compared to organic A+-site cations such as CH3NH3+ (MA+). Two NMR studies were conducted: 133Cs NMR analysis shows that Cs+ and MA+ compete for coordination with PbI3- in DMF. 207Pb NMR studies of PbI2 with cationic iodides show that perovskite-forming Cs+ (and, somewhat, Rb+) do not comport with the 207Pb chemical shift trend found for Li+, Na+, and K+. Three independent computational approaches (density functional theory (DFT), ab initio Molecular Dynamics (AIMD), and a polarizable force field within Molecular Dynamics) yielded strikingly similar results: Cs+ interacts more strongly with the PbI3- iodoplumbate than does MA+ in a polar solvent environment like DMF. The stronger energy preference for PbI3- coordination of Cs+ vs MA+ in DMF demonstrates that Cs+ is not simply a postcrystallization cation "fit" for the perovskite A+-site. Instead, it may facilitate preorganization of the framework precursor that eventually transforms into the crystalline perovskite structure.
Collapse
Affiliation(s)
- Yannick Eatmon
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Oluwaseun Romiluyi
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Connor Ganley
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Ruihao Ni
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - István Pelczer
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Paulette Clancy
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Barry P Rand
- Department of Electrical Engineering and Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
| | - Jeffrey Schwartz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
13
|
Smith HL, Dull JT, Mohapatra SK, Al Kurdi K, Barlow S, Marder SR, Rand BP, Kahn A. Powerful Organic Molecular Oxidants and Reductants Enable Ambipolar Injection in a Large-Gap Organic Homojunction Diode. ACS Appl Mater Interfaces 2022; 14:2381-2389. [PMID: 34978787 DOI: 10.1021/acsami.1c21302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Doping has proven to be a critical tool for enhancing the performance of organic semiconductors in devices like organic light-emitting diodes. However, the challenge in working with high-ionization-energy (IE) organic semiconductors is to find p-dopants with correspondingly high electron affinity (EA) that will improve the conductivity and charge carrier transport in a film. Here, we use an oxidant that has been recently recognized to be a very strong p-type dopant, hexacyano-1,2,3-trimethylene-cyclopropane (CN6-CP). The EA of CN6-CP has been previously estimated via cyclic voltammetry to be 5.87 eV, almost 300 meV higher than other known high-EA organic molecular oxidants. We measure the frontier orbitals of CN6-CP using ultraviolet and inverse photoemission spectroscopy techniques and confirm a high EA value of 5.88 eV in the condensed phase. The introduction of CN6-CP in a film of large-band-gap, large-IE phenyldi(pyren-1-yl)phosphine oxide (POPy2) leads to a significant shift of the Fermi level toward the highest occupied molecular orbital and a 2 orders of magnitude increase in conductivity. Using CN6-CP and n-dopant (pentamethylcyclopentadienyl)(1,3,5-trimethylbenzene)ruthenium (RuCp*Mes)2, we fabricate a POPy2-based rectifying p-i-n homojunction diode with a 2.9 V built-in potential. Blue light emission is achieved under forward bias. This effect demonstrates the dopant-enabled hole injection from the CN6-CP-doped layer and electron injection from the (RuCp*Mes)2-doped layer in the diode.
Collapse
Affiliation(s)
- Hannah L Smith
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Jordan T Dull
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Swagat K Mohapatra
- School of Chemistry and Biochemistry and Center for Organic Photonics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Department of Industrial and Engineering Chemistry, Institute of Chemical Technology─Indian Oil Odisha Campus, IIT Kharagpur Extension Center, Bhubaneswar 751013, Odisha, India
| | - Khaled Al Kurdi
- School of Chemistry and Biochemistry and Center for Organic Photonics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Stephen Barlow
- School of Chemistry and Biochemistry and Center for Organic Photonics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Seth R Marder
- School of Chemistry and Biochemistry and Center for Organic Photonics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department of Chemical and Biological Engineering and Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Barry P Rand
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
| | - Antoine Kahn
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
14
|
Dettmann MA, Cavalcante LSR, Magdaleno C, Masalkovaitė K, Vong D, Dull JT, Rand BP, Daemen LL, Goldman N, Faller R, Moulé AJ. Comparing the Expense and Accuracy of Methods to Simulate Atomic Vibrations in Rubrene. J Chem Theory Comput 2021; 17:7313-7320. [PMID: 34818006 DOI: 10.1021/acs.jctc.1c00747] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Atomic vibrations can inform about materials properties from hole transport in organic semiconductors to correlated disorder in metal-organic frameworks. Currently, there are several methods for predicting these vibrations using simulations, but the accuracy-efficiency tradeoffs have not been examined in depth. In this study, rubrene is used as a model system to predict atomic vibrational properties using six different simulation methods: density functional theory, density functional tight binding, density functional tight binding with a Chebyshev polynomial-based correction, a trained machine learning model, a pretrained machine learning model called ANI-1, and a classical forcefield model. The accuracy of each method is evaluated by comparison to the experimental inelastic neutron scattering spectrum. All methods discussed here show some accuracy across a wide energy region, though the Chebyshev-corrected tight-binding method showed the optimal combination of high accuracy with low expense. We then offer broad simulation guidelines to yield efficient, accurate results for inelastic neutron scattering spectrum prediction.
Collapse
Affiliation(s)
- Makena A Dettmann
- University of California Davis, Davis, California 95616, United States
| | | | - Corina Magdaleno
- University of California Davis, Davis, California 95616, United States
| | | | - Daniel Vong
- University of California Davis, Davis, California 95616, United States
| | - Jordan T Dull
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Luke L Daemen
- Oak Ridge National Lab, Oak Ridge, Tennessee 37831, United States
| | - Nir Goldman
- University of California Davis, Davis, California 95616, United States.,Lawrence Livermore National Lab, Livermore, California 94550, United States
| | - Roland Faller
- University of California Davis, Davis, California 95616, United States
| | - Adam J Moulé
- University of California Davis, Davis, California 95616, United States
| |
Collapse
|
15
|
Zhao L, Roh K, Kacmoli S, Al Kurdi K, Liu X, Barlow S, Marder SR, Gmachl C, Rand BP. Nanosecond-Pulsed Perovskite Light-Emitting Diodes at High Current Density. Adv Mater 2021; 33:e2104867. [PMID: 34477263 DOI: 10.1002/adma.202104867] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/02/2021] [Indexed: 06/13/2023]
Abstract
While metal-halide perovskite light-emitting diodes (PeLEDs) hold the potential for a new generation of display and lighting technology, their slow operation speed and response time limit their application scope. Here, high-speed PeLEDs driven by nanosecond electrical pulses with a rise time of 1.2 ns are reported with a maximum radiance of approximately 480 kW sr-1 m-2 at 8.3 kA cm-2 , and an external quantum efficiency (EQE) of 1% at approximately 10 kA cm-2 , through improved device configuration designs and material considerations. Enabled by the fast operation of PeLEDs, the temporal response provides access to transient charge carrier dynamics under electrical excitation, revealing several new electroluminescence quenching pathways. Finally, integrated distributed feedback (DFB) gratings are explored, which facilitate more directional light emission with a maximum radiance of approximately 1200 kW sr-1 m-2 at 8.5 kA cm-2 , a more than two-fold enhancement to forward radiation output.
Collapse
Affiliation(s)
- Lianfeng Zhao
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Kwangdong Roh
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Sara Kacmoli
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Khaled Al Kurdi
- School of Chemistry and Biochemistry, Center for Organic Electronics, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - Xiao Liu
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Stephen Barlow
- School of Chemistry and Biochemistry, Center for Organic Electronics, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - Seth R Marder
- School of Chemistry and Biochemistry, Center for Organic Electronics, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - Claire Gmachl
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| |
Collapse
|
16
|
Abstract
Enhanced delocalization is beneficial for absorbing molecules in organic solar cells, and in particular bilayer devices, where excitons face small diffusion lengths as a barrier to reaching the charge-generating donor-acceptor interface. As hybrid light-matter states, polaritons offer exceptional delocalization which could be used to improve the efficiency of bilayer organic photovoltaics. Polariton delocalization can aid in delivering excitons to the donor-acceptor interface, but the subsequent charge transfer event must compete with the fast decay of the polariton. To evaluate the viability of polaritons as tools to improve bilayer organic solar cells, we studied the decay of the lower polariton in three cavity systems: a donor only, a donor-acceptor bilayer, and a donor-acceptor blend. Using several spectroscopic techniques, we identified an additional decay pathway through charge transfer for the polariton in the bilayer cavity, demonstrating charge transfer from the polariton is fast enough to outcompete the decay to the ground state.
Collapse
Affiliation(s)
- Courtney A DelPo
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Saeed-Uz-Zaman Khan
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Kyu Hyung Park
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Bryan Kudisch
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Barry P Rand
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
| | - Gregory D Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
17
|
Schwarz KN, Mitchell VD, Khan SUZ, Lee C, Reinhold A, Smith TA, Ghiggino KP, Jones DJ, Rand BP, Scholes GD. Morphological Requirements for Nanoscale Electric Field Buildup in a Bulk Heterojunction Solar Cell. J Phys Chem Lett 2021; 12:537-545. [PMID: 33378206 DOI: 10.1021/acs.jpclett.0c03425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The morphology of organic semiconductors is critical to their function in optoelectronic devices and is particularly crucial in the donor-acceptor mixture that comprises the bulk heterojunction of organic solar cells. Here, energy landscapes can play integral roles in charge photogeneration, and recently have been shown to drive the accumulation of charge carriers away from the interface, resulting in the buildup of large nanoscale electric fields, much like a capacitor. In this work we combine morphological and spectroscopic data to outline the requirements for this interdomain charge accumulation, finding that this effect is driven by a three-phase morphology that creates an energetic cascade for charge carriers. By adjusting annealing conditions, we show that domain purity, but not size, is critical for an electro-absorption feature to grow-in. This demonstrates that the energy landscape around the interface shapes the movement of charges and that pure domains are required for charge carrier buildup that results in reduced recombination and large interdomain nanoscale electric fields.
Collapse
Affiliation(s)
- Kyra N Schwarz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Valerie D Mitchell
- Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168, Australia
| | | | | | - Adam Reinhold
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | | | | | | | | | - Gregory D Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
18
|
Londi G, Khan SUZ, Muccioli L, D'Avino G, Rand BP, Beljonne D. Fate of Low-Lying Charge-Transfer Excited States in a Donor:Acceptor Blend with a Large Energy Offset. J Phys Chem Lett 2020; 11:10219-10226. [PMID: 33206537 DOI: 10.1021/acs.jpclett.0c02858] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In an effort to gain a comprehensive picture of the interfacial states in bulk heterojunction solar cells, we provide a combined experimental-theoretical analysis of the energetics and dynamics of low-lying electronic charge-transfer (CT) states in donor:acceptor blends with a large frontier orbital energy offset. By varying the blend composition and temperature, we unravel the static and dynamic contributions to the disordered density of states (DOS) of the CT-state manifold and assess their recombination to the ground state. Namely, we find that static disorder (conformational and electrostatic) shapes the CT DOS and that fast nonradiative recombination crops the low-energy tail of the distribution probed by external quantum efficiency (EQE) measurements (thereby largely contributing to voltage losses). Our results then question the standard practice of extracting microscopic parameters such as exciton energy and energetic disorder from EQE.
Collapse
Affiliation(s)
- Giacomo Londi
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Saeed-Uz-Zaman Khan
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Luca Muccioli
- Department of Industrial Chemistry, University of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
| | - Gabriele D'Avino
- Grenoble Alpes University, CNRS, Grenoble INP, Institut Néel, 25 rue des Martyrs, 38042 Grenoble, France
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
| | - David Beljonne
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, 7000 Mons, Belgium
| |
Collapse
|
19
|
Zhao L, Roh K, Kacmoli S, Al Kurdi K, Jhulki S, Barlow S, Marder SR, Gmachl C, Rand BP. Thermal Management Enables Bright and Stable Perovskite Light-Emitting Diodes. Adv Mater 2020; 32:e2000752. [PMID: 32406172 DOI: 10.1002/adma.202000752] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 04/14/2020] [Accepted: 04/17/2020] [Indexed: 06/11/2023]
Abstract
The performance of lead-halide perovskite light-emitting diodes (LEDs) has increased rapidly in recent years. However, most reports feature devices operated at relatively small current densities (<500 mA cm-2 ) with moderate radiance (<400 W sr-1 m-2 ). Here, Joule heating and inefficient thermal dissipation are shown to be major obstacles toward high radiance and long lifetime. Several thermal management strategies are proposed in this work, such as doping charge-transport layers, optimizing device geometry, and attaching heat spreaders and sinks. Combining these strategies, high-performance perovskite LEDs are demonstrated with maximum radiance of 2555 W sr-1 m-2 , peak external quantum efficiency (EQE) of 17%, considerably reduced EQE roll-off (EQE > 10% to current densities as high as 2000 mA cm-2 ), and tenfold increase in operational lifetime (when driven at 100 mA cm-2 ). Furthermore, with proper thermal management, a maximum current density of 2.5 kA cm-2 and an EQE of ≈1% at 1 kA cm-2 are shown using electrical pulses, which represents an important milestone toward electrically driven perovskite lasers.
Collapse
Affiliation(s)
- Lianfeng Zhao
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Kwangdong Roh
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Sara Kacmoli
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Khaled Al Kurdi
- School of Chemistry and Biochemistry, Center for Organic Electronics, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - Samik Jhulki
- School of Chemistry and Biochemistry, Center for Organic Electronics, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - Stephen Barlow
- School of Chemistry and Biochemistry, Center for Organic Electronics, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - Seth R Marder
- School of Chemistry and Biochemistry, Center for Organic Electronics, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - Claire Gmachl
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| |
Collapse
|
20
|
DelPo C, Kudisch B, Park KH, Khan SUZ, Fassioli F, Fausti D, Rand BP, Scholes GD. Polariton Transitions in Femtosecond Transient Absorption Studies of Ultrastrong Light-Molecule Coupling. J Phys Chem Lett 2020; 11:2667-2674. [PMID: 32186878 PMCID: PMC8154840 DOI: 10.1021/acs.jpclett.0c00247] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Strong light-matter coupling is emerging as a fascinating way to tune optical properties and modify the photophysics of molecular systems. In this work, we studied a molecular chromophore under strong coupling with the optical mode of a Fabry-Perot cavity resonant to the first electronic absorption band. Using femtosecond pump-probe spectroscopy, we investigated the transient response of the cavity-coupled molecules upon photoexcitation resonant to the upper and lower polaritons. We identified an excited state absorption from upper and lower polaritons to a state at the energy of the second cavity mode. Quantum mechanical calculations of the many-molecule energy structure of cavity polaritons suggest assignment of this state as a two-particle polaritonic state with optically allowed transitions from the upper and lower polaritons. We provide new physical insight into the role of two-particle polaritonic states in explaining transient signatures in hybrid light-matter coupling systems consistent with analogous many-body systems.
Collapse
Affiliation(s)
- Courtney
A. DelPo
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Bryan Kudisch
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Kyu Hyung Park
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Saeed-Uz-Zaman Khan
- Department
of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Francesca Fassioli
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- SISSA−
Scuola Internazionale Superiore di Studi Avanzati, Trieste 34136, Italy
| | - Daniele Fausti
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department
of Physics, University of Trieste, Via A. Valerio 2, 34127 Trieste, Italy
- Elettra-Sincrotrone
Trieste S.C.p.A., Strada
Statale 14 - km 163.5 in AREA Science Park, 34149 Basovizza, Trieste, Italy
| | - Barry P. Rand
- Department
of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Andlinger
Center for Energy and the Environment, Princeton
University, Princeton, New Jersey 08544, United States
| | - Gregory D. Scholes
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
21
|
Schwarz KN, Geraghty PB, Mitchell VD, Khan SUZ, Sandberg OJ, Zarrabi N, Kudisch B, Subbiah J, Smith TA, Rand BP, Armin A, Scholes GD, Jones DJ, Ghiggino KP. Reduced Recombination and Capacitor-like Charge Buildup in an Organic Heterojunction. J Am Chem Soc 2020; 142:2562-2571. [PMID: 31922408 DOI: 10.1021/jacs.9b12526] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Organic photovoltaic (OPV) efficiencies continue to rise, raising their prospects for solar energy conversion. However, researchers have long considered how to suppress the loss of free carriers by recombination-poor diffusion and significant Coulombic attraction can cause electrons and holes to encounter each other at interfaces close to where they were photogenerated. Using femtosecond transient spectroscopies, we report the nanosecond grow-in of a large transient Stark effect, caused by nanoscale electric fields of ∼487 kV/cm between photogenerated free carriers in the device active layer. We find that particular morphologies of the active layer lead to an energetic cascade for charge carriers, suppressing pathways to recombination, which is ∼2000 times less than predicted by Langevin theory. This in turn leads to the buildup of electric charge in donor and acceptor domains-away from the interface-resistant to bimolecular recombination. Interestingly, this signal is only experimentally obvious in thick films due to the different scaling of electroabsorption and photoinduced absorption signals in transient absorption spectroscopy. Rather than inhibiting device performance, we show that devices up to 600 nm thick maintain efficiencies of >8% because domains can afford much higher carrier densities. These observations suggest that with particular nanoscale morphologies the bulk heterojunction can go beyond its established role in charge photogeneration and can act as a capacitor, where adjacent free charges are held away from the interface and can be protected from bimolecular recombination.
Collapse
Affiliation(s)
| | | | | | | | - Oskar J Sandberg
- Department of Physics , Swansea University , Singleton Park , Swansea , Wales SA2 8PP , United Kingdom
| | - Nasim Zarrabi
- Department of Physics , Swansea University , Singleton Park , Swansea , Wales SA2 8PP , United Kingdom
| | | | | | | | | | - Ardalan Armin
- Department of Physics , Swansea University , Singleton Park , Swansea , Wales SA2 8PP , United Kingdom
| | | | | | | |
Collapse
|
22
|
Lee TS, Lin YL, Kim H, Rand BP, Scholes GD. Two temperature regimes of triplet transfer in the dissociation of the correlated triplet pair after singlet fission. CAN J CHEM 2019. [DOI: 10.1139/cjc-2018-0421] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ability to undergo spin-allowed exciton multiplication makes singlet fission materials promising for photovoltaic applications. Here, we examine the separation of correlated triplet pairs, 1(T…T), in polycrystalline pentacene films via temperature-dependent transient absorption spectroscopy. Single wavelength analysis reveals a profound delay in 1(T…T) dynamics. Moreover, the dynamics of 1(T…T) exhibit temperature dependence, whereas other features show no discernable temperature dependence. Previous literatures have suggested that correlated triplet separation is mediated by a thermally activated hopping process. Surprisingly, we found that the time constants governing triplet pair separation display two distinct temperature-dependent regimes of triplet transport. The high temperature regime follows a thermally activated hopping mechanism. The experimentally derived reorganization energy and electronic coupling is verified by density matrix renormalization group quantum chemical calculations. In addition, we evaluated the low temperature regime and show that the trend can be modelled by a Miller–Abrahams-type model that incorporates the effects of energetic disorder. We conclude that the correlated triplet pair separation is mediated by thermally activated hopping or a disorder driven Miller–Abrahams-type mechanism at high and low temperature, respectively. We observe that crossover between two regimes occurs ∼226 K. We find the time constant for triplet–triplet energy transfer to be 1.8 ps at ambient temperature and 21 ps at 77 K.
Collapse
Affiliation(s)
- Tia S. Lee
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - YunHui L. Lin
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Hwon Kim
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Barry P. Rand
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ 08544, USA
| | | |
Collapse
|
23
|
Abstract
Next-generation displays and lighting technologies require efficient optical sources that combine brightness, color purity, stability, substrate flexibility. Metal halide perovskites have potential use in a wide range of applications, for they possess excellent charge transport, bandgap tunability and, in the most promising recent optical source materials, intense and efficient luminescence. This review links metal halide perovskites' performance as efficient light emitters with their underlying materials electronic and photophysical attributes.
Collapse
Affiliation(s)
- Li Na Quan
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
| | - Barry P Rand
- Department of Electrical Engineering and Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
| | - Richard H Friend
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Subodh Gautam Mhaisalkar
- Energy Research Institute, Nanyang Technological University, Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, 637553 Singapore, Singapore
| | - Tae-Woo Lee
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Edward H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
| |
Collapse
|
24
|
Kong YL, Tamargo IA, Kim H, Johnson BN, Gupta MK, Koh TW, Chin HA, Steingart DA, Rand BP, McAlpine MC. Correction to 3D Printed Quantum Dot Light-Emitting Diodes. Nano Lett 2019; 19:2187. [PMID: 30776242 DOI: 10.1021/acs.nanolett.9b00598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
|
25
|
Zhang F, Ullrich F, Silver S, Kerner RA, Rand BP, Kahn A. Complexities of Contact Potential Difference Measurements on Metal Halide Perovskite Surfaces. J Phys Chem Lett 2019; 10:890-896. [PMID: 30739454 DOI: 10.1021/acs.jpclett.8b03878] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Understanding the stability of metal halide perovskite (MHP) surfaces is of considerable interest for the development of devices based on these materials. We present here a vacuum-based study of the surface potential and response to illumination of two different types of perovskite films, methylammonium lead bromide (MAPbBr3) and the 2D Ruddlesden-Popper phase butylammonium lead iodide (BA2PbI4, n = 1), using Kelvin probe-based contact potential difference and surface photovoltage measurements. We show that supraband gap light irradiation can induce the loss of halide species, which adsorb on the Kelvin probe tip, inducing quasi-irreversible changes of the MHP surface and tip work functions. If undetected, this can lead to misinterpretations of the MHP surface potential. Our results illustrate the effectiveness of the Kelvin probe-based technique in providing complementary information on the energetics of perovskite surfaces and the necessity to monitor the work function of the probe to avoid erroneous conclusions when working on these materials.
Collapse
Affiliation(s)
- Fengyu Zhang
- Department of Electrical Engineering , Princeton University , Princeton , New Jersey 08544 , United States
| | - Florian Ullrich
- Materials Science Department , Technische Universität Darmstadt , 64287 Darmstadt , Germany
| | - Scott Silver
- Department of Electrical Engineering , Princeton University , Princeton , New Jersey 08544 , United States
| | - Ross A Kerner
- Department of Electrical Engineering , Princeton University , Princeton , New Jersey 08544 , United States
| | - Barry P Rand
- Department of Electrical Engineering , Princeton University , Princeton , New Jersey 08544 , United States
- Andlinger Center for Energy and the Environment , Princeton University , Princeton , New Jersey 08544 , United States
| | - Antoine Kahn
- Department of Electrical Engineering , Princeton University , Princeton , New Jersey 08544 , United States
| |
Collapse
|
26
|
Jeon S, Zhao L, Jung YJ, Kim JW, Kim SY, Kang H, Jeong JH, Rand BP, Lee JH. Perovskite Light-Emitting Diodes with Improved Outcoupling Using a High-Index Contrast Nanoarray. Small 2019; 15:e1900135. [PMID: 30701678 DOI: 10.1002/smll.201900135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Indexed: 05/21/2023]
Abstract
Organic-inorganic hybrid perovskite light-emitting diodes (PeLEDs) are promising for next-generation optoelectronic devices due to their potential to achieve high color purity, efficiency, and brightness. Although the external quantum efficiency (EQE) of PeLEDs has recently surpassed 20%, various strategies are being pursued to increase EQE further and reduce the EQE gap compared to other LED technologies. A key point to further boost EQE of PeLEDs is linked to the high refractive index of the perovskite emissive layer, leading to optical losses of more than 70% of emitted photons. Here, it is demonstrated that a randomly distributed nanohole array with high-index contrast can effectively enhance outcoupling efficiency in PeLEDs. Based on a comprehensive optical analysis on the perovskite thin film and outcoupling structure, it is confirmed that the nanohole array effectively distributes light into the substrate for improved outcoupling, allowing for 1.64 times higher light extraction. As a result, highly efficient red/near-infrared PeLEDs with a peak EQE of 14.6% are demonstrated.
Collapse
Affiliation(s)
- Sohee Jeon
- Nano-Convergence Mechanical Research Division, Korea Institute of Machinery and Materials (KIMM), Yuseong-gu, Daejeon, 34103, Republic of Korea
| | - Lianfeng Zhao
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Young-Jin Jung
- Department of Materials Science and Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea
| | - Ji Whan Kim
- Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Sei-Yong Kim
- LG Chem. Research Park, LG Chem. Co., Ltd., 188 Munji-ro, Yuseong-gu, Daejeon, 34122, Republic of Korea
| | - Hyeokjung Kang
- Nano-Convergence Mechanical Research Division, Korea Institute of Machinery and Materials (KIMM), Yuseong-gu, Daejeon, 34103, Republic of Korea
| | - Jun-Ho Jeong
- Nano-Convergence Mechanical Research Division, Korea Institute of Machinery and Materials (KIMM), Yuseong-gu, Daejeon, 34103, Republic of Korea
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| | - Jeong-Hwan Lee
- Department of Materials Science and Engineering, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea
| |
Collapse
|
27
|
Zhao L, Lee KM, Roh K, Khan SUZ, Rand BP. Improved Outcoupling Efficiency and Stability of Perovskite Light-Emitting Diodes using Thin Emitting Layers. Adv Mater 2019; 31:e1805836. [PMID: 30412319 DOI: 10.1002/adma.201805836] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 10/08/2018] [Indexed: 05/21/2023]
Abstract
Hybrid organic-inorganic perovskite semiconductors have shown potential to develop into a new generation of light-emitting diode (LED) technology. Herein, an important design principle for perovskite LEDs is elucidated regarding optimal perovskite thickness. Adopting a thin perovskite layer in the range of 35-40 nm is shown to be critical for both device efficiency and stability improvements. Maximum external quantum efficiencies (EQEs) of 17.6% for Cs0.2 FA0.8 PbI2.8 Br0.2 , 14.3% for CH3 NH3 PbI3 (MAPbI3 ), 10.1% for formamidinium lead iodide (FAPbI3 ), and 11.3% for formamidinium lead bromide (FAPbBr3 )-based LEDs are demonstrated with optimized perovskite layer thickness. Optical simulations show that the improved EQEs source from improved light outcoupling. Furthermore, elevated device temperature caused by Joule heating is shown as an important factor contributing to device degradation, and that thin perovskite emitting layers maintain lower junction temperature during operation and thus demonstrate increased stability.
Collapse
Affiliation(s)
- Lianfeng Zhao
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Kyung Min Lee
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Kwangdong Roh
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Saeed Uz Zaman Khan
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| |
Collapse
|
28
|
Qiu W, Xiao Z, Roh K, Noel NK, Shapiro A, Heremans P, Rand BP. Mixed Lead-Tin Halide Perovskites for Efficient and Wavelength-Tunable Near-Infrared Light-Emitting Diodes. Adv Mater 2019; 31:e1806105. [PMID: 30484911 DOI: 10.1002/adma.201806105] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 11/04/2018] [Indexed: 05/25/2023]
Abstract
Near-infrared (NIR) light-emitting diodes (LEDs), with emission wavelengths between 800 and 950 nm, are useful for various applications, e.g., night-vision devices, optical communication, and medical treatments. Yet, devices using thin film materials like organic semiconductors and lead based colloidal quantum dots face certain fundamental challenges that limit the improvement of external quantum efficiency (EQE), making the search of alternative NIR emitters important for the community. In this work, efficient NIR LEDs with tunable emission from 850 to 950 nm, using lead-tin (Pb-Sn) halide perovskite as emitters are demonstrated. The best performing device exhibits an EQE of 5.0% with a peak emission wavelength of 917 nm, a turn-on voltage of 1.65 V, and a radiance of 2.7 W Sr-1 m-2 when driven at 4.5 V. The emission spectra of mixed Pb-Sn perovskites are tuned either by changing the Pb:Sn ratio or by incorporating bromide, and notably exhibit no phase separation during device operation. The work demonstrates that mixed Pb-Sn perovskites are promising next generation NIR emitters.
Collapse
Affiliation(s)
- Weiming Qiu
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
- Imec, Kapeldreef 75, Heverlee, 3001, Belgium
- Department of Electrical Engineering, ESAT, KU Leuven, Heverlee, 3001, Belgium
| | - Zhengguo Xiao
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
- Department of Physics, Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology, Hefei, Anhui, 230026, China
| | - Kwangdong Roh
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Nakita K Noel
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
- Princeton Research Institute for the Science and Technology of Materials, Princeton University, Princeton, NJ, 08544, USA
| | - Andrew Shapiro
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Paul Heremans
- Imec, Kapeldreef 75, Heverlee, 3001, Belgium
- Department of Electrical Engineering, ESAT, KU Leuven, Heverlee, 3001, Belgium
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| |
Collapse
|
29
|
Lee KM, Phillips O, Engler A, Kohl PA, Rand BP. Phototriggered Depolymerization of Flexible Poly(phthalaldehyde) Substrates by Integrated Organic Light-Emitting Diodes. ACS Appl Mater Interfaces 2018; 10:28062-28068. [PMID: 30040372 DOI: 10.1021/acsami.8b08181] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We demonstrate phototriggered depolymerization of a low ceiling temperature ( Tc) polymer, poly(phthalaldehyde) (PPHA), via internal light emission from integrated organic light-emitting diodes (OLEDs) fabricated directly on flexible PPHA substrates with silver nanowire electrodes. The depolymerization of the PPHA substrates is triggered by absorption of the OLED emission by a sensitizer that activates a photoacid generator via energetically favorable electron transfer. We confirm with Fourier-transform infrared spectroscopy that the photon doses delivered by the integrated OLED are sufficient to depolymerize the PPHA substrates. We determine this critical dosage by measuring the operating lifetimes of the OLEDs whose failure is believed to be due to significant mechanical softening during the liquefaction of decomposed phthalaldehyde monomers.
Collapse
Affiliation(s)
- Kyung Min Lee
- Department of Electrical Engineering , Princeton University , Princeton , New Jersey 08544 , United States
| | - Oluwadamilola Phillips
- Department of Chemical and Biomolecular Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332-0100 , United States
| | - Anthony Engler
- Department of Chemical and Biomolecular Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332-0100 , United States
| | - Paul A Kohl
- Department of Chemical and Biomolecular Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332-0100 , United States
| | - Barry P Rand
- Department of Electrical Engineering , Princeton University , Princeton , New Jersey 08544 , United States
- Andlinger Center for Energy and the Environment , Princeton University , Princeton , New Jersey 08544 , United States
| |
Collapse
|
30
|
Abbasi K, Wang D, Fusella MA, Rand BP, Avishai A. Methods for Conducting Electron Backscattered Diffraction (EBSD) on Polycrystalline Organic Molecular Thin Films. Microsc Microanal 2018; 24:420-423. [PMID: 29925461 DOI: 10.1017/s1431927618000442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Electron backscattered diffraction (EBSD) is a technique regularly used to obtain crystallographic information from inorganic samples. When EBSD is acquired simultaneously with emitting diodes data, a sample can be thoroughly characterized both structurally and compositionally. For organic materials, coherent Kikuchi patterns do form when the electron beam interacts with crystalline material. However, such patterns tend to be weak due to the low average atomic number of organic materials. This is compounded by the fact that the patterns fade quickly and disappear completely once a critical electron dose is exceeded, inhibiting successful collection of EBSD maps from them. In this study, a new approach is presented that allows successful collection of EBSD maps from organic materials, here the extreme example of a hydrocarbon organic molecular thin film, and opens new avenues of characterization for crystalline organic materials.
Collapse
Affiliation(s)
- Kevin Abbasi
- 1Swagelok Center for Surface Analysis of Materials,Case School of Engineering,Case Western Reserve University,Cleveland,OH 44106,USA
| | - Danqi Wang
- 1Swagelok Center for Surface Analysis of Materials,Case School of Engineering,Case Western Reserve University,Cleveland,OH 44106,USA
| | - Michael A Fusella
- 2Department of Electrical Engineering,Princeton University,Princeton,NJ 08544,USA
| | - Barry P Rand
- 2Department of Electrical Engineering,Princeton University,Princeton,NJ 08544,USA
| | - Amir Avishai
- 1Swagelok Center for Surface Analysis of Materials,Case School of Engineering,Case Western Reserve University,Cleveland,OH 44106,USA
| |
Collapse
|
31
|
Lee TS, Lin YL, Kim H, Pensack RD, Rand BP, Scholes GD. Triplet Energy Transfer Governs the Dissociation of the Correlated Triplet Pair in Exothermic Singlet Fission. J Phys Chem Lett 2018; 9:4087-4095. [PMID: 29976063 DOI: 10.1021/acs.jpclett.8b01834] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Singlet fission is a spin-allowed process of exciton multiplication that has the potential to enhance the efficiency of photovoltaic devices. The majority of studies to date have emphasized understanding the first step of singlet fission, where the correlated triplet pair is produced. Here, we examine separation of correlated triplet pairs. We conducted temperature-dependent transient absorption on 6,3-bis(tri isopropylsilylethynyl)pentacene (TIPS-Pn) films, where singlet fission is exothermic. We evaluated time constants to show that their temperature dependence is inconsistent with an exclusively thermally activated process. Instead, we found that the trends can be modeled by a triplet-triplet energy transfer. The fitted reorganization energy and electronic coupling agree closely with values calculated using density matrix renormalization group quantum-chemical theory. We conclude that dissociation of the correlated triplet pair to separated (but spin-entangled) triplet excitons in TIPS-Pn occurs by triplet-triplet energy transfer with a hopping time constant of approximately 3.5 ps at room temperature.
Collapse
Affiliation(s)
- Tia S Lee
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - YunHui L Lin
- Department of Electrical Engineering , Princeton University , Princeton , New Jersey 08544 , United States
| | - Hwon Kim
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - Ryan D Pensack
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| | - Barry P Rand
- Department of Electrical Engineering , Princeton University , Princeton , New Jersey 08544 , United States
- Andlinger Center for Energy and the Environment , Princeton University , Princeton , New Jersey 08544 , United States
| | - Gregory D Scholes
- Department of Chemistry , Princeton University , Princeton , New Jersey 08544 , United States
| |
Collapse
|
32
|
Lin X, Wegner B, Lee KM, Fusella MA, Zhang F, Moudgil K, Rand BP, Barlow S, Marder SR, Koch N, Kahn A. Corrigendum: Beating the thermodynamic limit with photo-activation of n-doping in organic semiconductors. Nat Mater 2018; 17:204. [PMID: 29358767 DOI: 10.1038/nmat5067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This corrects the article DOI: 10.1038/nmat5027.
Collapse
|
33
|
Kerner RA, Rand BP. Ionic-Electronic Ambipolar Transport in Metal Halide Perovskites: Can Electronic Conductivity Limit Ionic Diffusion? J Phys Chem Lett 2018; 9:132-137. [PMID: 29260875 DOI: 10.1021/acs.jpclett.7b02401] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Ambipolar transport describes the nonequilibrium, coupled motion of positively and negatively charged particles to ensure that internal electric fields remain small. It is commonly invoked in the semiconductor community where the motion of excess electrons and holes drift and diffuse together. However, the concept of ambipolar transport is not limited to semiconductor physics. Materials scientists working on ion conducting ceramics understand ambipolar transport dictates the coupled diffusion of ions and the rate is limited by the ion with the lowest diffusion coefficient. In this Perspective, we review a third application of ambipolar transport relevant to mixed ionic-electronic conducting materials for which the motion of ions is expected to be coupled to electronic carriers. In this unique situation, the ambipolar diffusion model has been successful at explaining the photoenhanced diffusion of metal ions in chalcogenide glasses and other properties of materials. Recent examples of photoenhanced phenomena in metal halide perovskites are discussed and indicate that mixed ionic-electronic ambipolar transport is similarly important for a deep understanding of these emerging materials.
Collapse
Affiliation(s)
- Ross A Kerner
- Department of Electrical Engineering and ‡Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Barry P Rand
- Department of Electrical Engineering and ‡Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| |
Collapse
|
34
|
Tian H, Zhao L, Wang X, Yeh YW, Yao N, Rand BP, Ren TL. Extremely Low Operating Current Resistive Memory Based on Exfoliated 2D Perovskite Single Crystals for Neuromorphic Computing. ACS Nano 2017; 11:12247-12256. [PMID: 29200259 DOI: 10.1021/acsnano.7b05726] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Extremely low energy consumption neuromorphic computing is required to achieve massively parallel information processing on par with the human brain. To achieve this goal, resistive memories based on materials with ionic transport and extremely low operating current are required. Extremely low operating current allows for low power operation by minimizing the program, erase, and read currents. However, materials currently used in resistive memories, such as defective HfOx, AlOx, TaOx, etc., cannot suppress electronic transport (i.e., leakage current) while allowing good ionic transport. Here, we show that 2D Ruddlesden-Popper phase hybrid lead bromide perovskite single crystals are promising materials for low operating current nanodevice applications because of their mixed electronic and ionic transport and ease of fabrication. Ionic transport in the exfoliated 2D perovskite layer is evident via the migration of bromide ions. Filaments with a diameter of approximately 20 nm are visualized, and resistive memories with extremely low program current down to 10 pA are achieved, a value at least 1 order of magnitude lower than conventional materials. The ionic migration and diffusion as an artificial synapse is realized in the 2D layered perovskites at the pA level, which can enable extremely low energy neuromorphic computing.
Collapse
Affiliation(s)
- He Tian
- Institute of Microelectronics and Tsinghua National Laboratory for Information Science and Technology (TNList), Tsinghua University , Beijing 100084, China
| | - Lianfeng Zhao
- Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States
| | - Xuefeng Wang
- Institute of Microelectronics and Tsinghua National Laboratory for Information Science and Technology (TNList), Tsinghua University , Beijing 100084, China
| | - Yao-Wen Yeh
- Princeton Institute for Science and Technology of Materials, Princeton University , Princeton, New Jersey 08544, United States
| | - Nan Yao
- Princeton Institute for Science and Technology of Materials, Princeton University , Princeton, New Jersey 08544, United States
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Tian-Ling Ren
- Institute of Microelectronics and Tsinghua National Laboratory for Information Science and Technology (TNList), Tsinghua University , Beijing 100084, China
| |
Collapse
|
35
|
Lin X, Wegner B, Lee KM, Fusella MA, Zhang F, Moudgil K, Rand BP, Barlow S, Marder SR, Koch N, Kahn A. Beating the thermodynamic limit with photo-activation of n-doping in organic semiconductors. Nat Mater 2017; 16:1209-1215. [PMID: 29170548 DOI: 10.1038/nmat5027] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 10/06/2017] [Indexed: 06/07/2023]
Abstract
Chemical doping of organic semiconductors using molecular dopants plays a key role in the fabrication of efficient organic electronic devices. Although a variety of stable molecular p-dopants have been developed and successfully deployed in devices in the past decade, air-stable molecular n-dopants suitable for materials with low electron affinity are still elusive. Here we demonstrate that photo-activation of a cleavable air-stable dimeric dopant can result in kinetically stable and efficient n-doping of host semiconductors, whose reduction potentials are beyond the thermodynamic reach of the dimer's effective reducing strength. Electron-transport layers doped in this manner are used to fabricate high-efficiency organic light-emitting diodes. Our strategy thus enables a new paradigm for using air-stable molecular dopants to improve conductivity in, and provide ohmic contacts to, organic semiconductors with very low electron affinity.
Collapse
Affiliation(s)
- Xin Lin
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Berthold Wegner
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 16, D-12489 Berlin, Germany
- Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 6, D-12489 Berlin, Germany
| | - Kyung Min Lee
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Michael A Fusella
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Fengyu Zhang
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Karttikay Moudgil
- Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, USA
| | - Stephen Barlow
- Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Seth R Marder
- Center for Organic Photonics and Electronics and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Norbert Koch
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 16, D-12489 Berlin, Germany
- Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 6, D-12489 Berlin, Germany
| | - Antoine Kahn
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| |
Collapse
|
36
|
Xiao Z, Zhao L, Tran NL, Lin YL, Silver SH, Kerner RA, Yao N, Kahn A, Scholes GD, Rand BP. Mixed-Halide Perovskites with Stabilized Bandgaps. Nano Lett 2017; 17:6863-6869. [PMID: 28968126 DOI: 10.1021/acs.nanolett.7b03179] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
One merit of organic-inorganic hybrid perovskites is their tunable bandgap by adjusting the halide stoichiometry, an aspect critical to their application in tandem solar cells, wavelength-tunable light emitting diodes (LEDs), and lasers. However, the phase separation of mixed-halide perovskites caused by light or applied bias results in undesirable recombination at iodide-rich domains, meaning open-circuit voltage (VOC) pinning in solar cells and infrared emission in LEDs. Here, we report an approach to suppress halide redistribution by self-assembled long-chain organic ammonium capping layers at nanometer-sized grain surfaces. Using the stable mixed-halide perovskite films, we are able to fabricate efficient and wavelength-tunable perovskite LEDs from infrared to green with high external quantum efficiencies of up to 5%, as well as linearly tuned VOC from 1.05 to 1.45 V in solar cells.
Collapse
Affiliation(s)
- Zhengguo Xiao
- Department of Electrical Engineering, ‡Department of Chemistry, §Princeton Institute for the Science and Technology of Materials, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Lianfeng Zhao
- Department of Electrical Engineering, ‡Department of Chemistry, §Princeton Institute for the Science and Technology of Materials, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Nhu L Tran
- Department of Electrical Engineering, ‡Department of Chemistry, §Princeton Institute for the Science and Technology of Materials, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Yunhui Lisa Lin
- Department of Electrical Engineering, ‡Department of Chemistry, §Princeton Institute for the Science and Technology of Materials, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Scott H Silver
- Department of Electrical Engineering, ‡Department of Chemistry, §Princeton Institute for the Science and Technology of Materials, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Ross A Kerner
- Department of Electrical Engineering, ‡Department of Chemistry, §Princeton Institute for the Science and Technology of Materials, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Nan Yao
- Department of Electrical Engineering, ‡Department of Chemistry, §Princeton Institute for the Science and Technology of Materials, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Antoine Kahn
- Department of Electrical Engineering, ‡Department of Chemistry, §Princeton Institute for the Science and Technology of Materials, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Gregory D Scholes
- Department of Electrical Engineering, ‡Department of Chemistry, §Princeton Institute for the Science and Technology of Materials, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Barry P Rand
- Department of Electrical Engineering, ‡Department of Chemistry, §Princeton Institute for the Science and Technology of Materials, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| |
Collapse
|
37
|
Zhao L, Gao J, Lin YL, Yeh YW, Lee KM, Yao N, Loo YL, Rand BP. Electrical Stress Influences the Efficiency of CH 3 NH 3 PbI 3 Perovskite Light Emitting Devices. Adv Mater 2017; 29. [PMID: 28437033 DOI: 10.1002/adma.201605317] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 03/14/2017] [Indexed: 05/16/2023]
Abstract
Organic-inorganic hybrid perovskite materials are emerging as semiconductors with potential application in optoelectronic devices. In particular, perovskites are very promising for light-emitting devices (LEDs) due to their high color purity, low nonradiative recombination rates, and tunable bandgap. Here, using pure CH3 NH3 PbI3 perovskite LEDs with an external quantum efficiency (EQE) of 5.9% as a platform, it is shown that electrical stress can influence device performance significantly, increasing the EQE from an initial 5.9% to as high as 7.4%. Consistent with the enhanced device performance, both the steady-state photoluminescence (PL) intensity and the time-resolved PL decay lifetime increase after electrical stress, indicating a reduction in nonradiative recombination in the perovskite film. By investigating the temperature-dependent characteristics of the perovskite LEDs and the cross-sectional elemental depth profile, it is proposed that trap reduction and resulting device-performance enhancement is due to local ionic motion of excess ions, likely excess mobile iodide, in the perovskite film that fills vacancies and reduces interstitial defects. On the other hand, it is found that overstressed LEDs show irreversibly degraded device performance, possibly because ions initially on the perovskite lattice are displaced during extended electrical stress and create defects such as vacancies.
Collapse
Affiliation(s)
- Lianfeng Zhao
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Jia Gao
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - YunHui L Lin
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Yao-Wen Yeh
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, 08544, USA
| | - Kyung Min Lee
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Nan Yao
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, 08544, USA
| | - Yueh-Lin Loo
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| |
Collapse
|
38
|
Abstract
We demonstrate that reversible chemical reactions occur at TiO2/gas and CH3NH3PbI3/gas interfaces on a time scale of seconds to minutes. The chemisorption strongly affects their electronic properties, mainly acting to deplete TiO2 of free electrons and passivate surface traps on the perovskite. Although the chemistry is not directly probed, we infer that reversible chemistry occurs at the solid-state TiO2/CH3NH3PbI3 interface. Equilibrium or steady-state concentrations established for adsorbed species associated with each material would be voltage- and illumination-dependent due to free or photocarriers being a main reactant. Interfacial chemistry provides an additional physical mechanism to explain the origins of normal and anomalous hysteretic current-voltage characteristics of perovskite devices. Furthermore, chemical reactions help us to understand why measured perovskite ion-transport properties and the nature of hysteresis are highly dependent on interfaces.
Collapse
Affiliation(s)
- Ross A Kerner
- Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| |
Collapse
|
39
|
Abstract
The smooth surface of crystalline rubrene films formed through an abrupt heating process provides a valuable platform to study organic homoepitaxy. By varying growth rate and substrate temperature, we are able to manipulate the onset of a transition from layer-by-layer to island growth modes, while the crystalline thin films maintain a remarkably smooth surface (less than 2.3 nm root-mean-square roughness) even with thick (80 nm) adlayers. We also uncover evidence of point and line defect formation in these films, indicating that homoepitaxy under our conditions is not at equilibrium or strain-free. Point defects that are resolved as screw dislocations can be eliminated under closer-to-equilibrium conditions, whereas we are not able to eliminate the formation of line defects within our experimental constraints at adlayer thicknesses above ∼25 nm. We are, however, able to eliminate these line defects by growing on a bulk single crystal of rubrene, indicating that the line defects are a result of strain built into the thin film template. We utilize electron backscatter diffraction, which is a first for organics, to investigate the origin of these line defects and find that they preferentially occur parallel to the (002) plane, which is in agreement with expectations based on calculated surface energies of various rubrene crystal facets. By combining the benefits of crystallinity, low surface roughness, and thickness-tunability, this system provides an important study of attributes valuable to high-performance organic electronic devices.
Collapse
Affiliation(s)
- Michael A Fusella
- Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544 United States
| | - Frank Schreiber
- Institut für Angewandte Physik, Universität Tübingen , Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Kevin Abbasi
- Swagelok Center for Surface Analysis of Materials, Case Western Reserve University , Cleveland, Ohio 44106 United States
| | - Jae Joon Kim
- Polymer Science and Engineering, University of Massachusetts , Amherst, Massachusetts 01003 United States
| | - Alejandro L Briseno
- Polymer Science and Engineering, University of Massachusetts , Amherst, Massachusetts 01003 United States
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544 United States
- Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544 United States
| |
Collapse
|
40
|
Zhao L, Yeh YW, Tran NL, Wu F, Xiao Z, Kerner RA, Lin YL, Scholes GD, Yao N, Rand BP. In Situ Preparation of Metal Halide Perovskite Nanocrystal Thin Films for Improved Light-Emitting Devices. ACS Nano 2017; 11:3957-3964. [PMID: 28332818 DOI: 10.1021/acsnano.7b00404] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Hybrid organic-inorganic halide perovskite semiconductors are attractive candidates for optoelectronic applications, such as photovoltaics, light-emitting diodes, and lasers. Perovskite nanocrystals are of particular interest, where electrons and holes can be confined spatially, promoting radiative recombination. However, nanocrystalline films based on traditional colloidal nanocrystal synthesis strategies suffer from the use of long insulating ligands, low colloidal nanocrystal concentration, and significant aggregation during film formation. Here, we demonstrate a facile method for preparing perovskite nanocrystal films in situ and that the electroluminescence of light-emitting devices can be enhanced up to 40-fold through this nanocrystal film formation strategy. Briefly, the method involves the use of bulky organoammonium halides as additives to confine crystal growth of perovskites during film formation, achieving CH3NH3PbI3 and CH3NH3PbBr3 perovskite nanocrystals with an average crystal size of 5.4 ± 0.8 nm and 6.4 ± 1.3 nm, respectively, as confirmed through transmission electron microscopy measurements. Additive-confined perovskite nanocrystals show significantly improved photoluminescence quantum yield and decay lifetime. Finally, we demonstrate highly efficient CH3NH3PbI3 red/near-infrared LEDs and CH3NH3PbBr3 green LEDs based on this strategy, achieving an external quantum efficiency of 7.9% and 7.0%, respectively, which represent a 40-fold and 23-fold improvement over control devices fabricated without the additives.
Collapse
Affiliation(s)
- Lianfeng Zhao
- Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Yao-Wen Yeh
- Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Nhu L Tran
- Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Fan Wu
- Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Zhengguo Xiao
- Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Ross A Kerner
- Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - YunHui L Lin
- Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Gregory D Scholes
- Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Nan Yao
- Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Barry P Rand
- Department of Electrical Engineering, ‡Princeton Institute for Science and Technology of Materials, §Department of Chemistry, and ∥Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| |
Collapse
|
41
|
Endres J, Egger D, Kulbak M, Kerner RA, Zhao L, Silver SH, Hodes G, Rand BP, Cahen D, Kronik L, Kahn A. Valence and Conduction Band Densities of States of Metal Halide Perovskites: A Combined Experimental-Theoretical Study. J Phys Chem Lett 2016; 7:2722-9. [PMID: 27364125 PMCID: PMC4959026 DOI: 10.1021/acs.jpclett.6b00946] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/01/2016] [Indexed: 05/05/2023]
Abstract
We report valence and conduction band densities of states measured via ultraviolet and inverse photoemission spectroscopies on three metal halide perovskites, specifically methylammonium lead iodide and bromide and cesium lead bromide (MAPbI3, MAPbBr3, CsPbBr3), grown at two different institutions on different substrates. These are compared with theoretical densities of states (DOS) calculated via density functional theory. The qualitative agreement achieved between experiment and theory leads to the identification of valence and conduction band spectral features, and allows a precise determination of the position of the band edges, ionization energy and electron affinity of the materials. The comparison reveals an unusually low DOS at the valence band maximum (VBM) of these compounds, which confirms and generalizes previous predictions of strong band dispersion and low DOS at the MAPbI3 VBM. This low DOS calls for special attention when using electron spectroscopy to determine the frontier electronic states of lead halide perovskites.
Collapse
Affiliation(s)
- James Endres
- Department
of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - David
A. Egger
- Department
of Materials and Interfaces, Weizmann Institute
of Science, Rehovoth, 76100, Israel
| | - Michael Kulbak
- Department
of Materials and Interfaces, Weizmann Institute
of Science, Rehovoth, 76100, Israel
| | - Ross A. Kerner
- Department
of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Lianfeng Zhao
- Department
of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Scott H. Silver
- Department
of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Gary Hodes
- Department
of Materials and Interfaces, Weizmann Institute
of Science, Rehovoth, 76100, Israel
| | - Barry P. Rand
- Department
of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - David Cahen
- Department
of Materials and Interfaces, Weizmann Institute
of Science, Rehovoth, 76100, Israel
| | - Leeor Kronik
- Department
of Materials and Interfaces, Weizmann Institute
of Science, Rehovoth, 76100, Israel
| | - Antoine Kahn
- Department
of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, United States
| |
Collapse
|
42
|
Jia Y, Kerner RA, Grede AJ, Brigeman AN, Rand BP, Giebink NC. Diode-Pumped Organo-Lead Halide Perovskite Lasing in a Metal-Clad Distributed Feedback Resonator. Nano Lett 2016; 16:4624-9. [PMID: 27331618 DOI: 10.1021/acs.nanolett.6b01946] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Organic-inorganic lead halide perovskite semiconductors have recently reignited the prospect of a tunable, solution-processed diode laser, which has the potential to impact a wide range of optoelectronic applications. Here, we demonstrate a metal-clad, second-order distributed feedback methylammonium lead iodide perovskite laser that marks a significant step toward this goal. Optically pumping this device with an InGaN diode laser at low temperature, we achieve lasing above a threshold pump intensity of 5 kW/cm(2) for durations up to ∼25 ns at repetition rates exceeding 2 MHz. We show that the lasing duration is not limited by thermal runaway and propose instead that lasing ceases under continuous pumping due to a photoinduced structural change in the perovskite that reduces the gain on a submicrosecond time scale. Our results indicate that the architecture demonstrated here could provide the foundation for electrically pumped lasing with a threshold current density Jth < 5 kA/cm(2) under sub-20 ns pulsed drive.
Collapse
Affiliation(s)
- Yufei Jia
- Department of Electrical Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Ross A Kerner
- Department of Electrical Engineering and Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Alex J Grede
- Department of Electrical Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Alyssa N Brigeman
- Department of Electrical Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Barry P Rand
- Department of Electrical Engineering and Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Noel C Giebink
- Department of Electrical Engineering, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| |
Collapse
|
43
|
Kozlov OV, de Haan F, Kerner RA, Rand BP, Cheyns D, Pshenichnikov MS. Real-Time Tracking of Singlet Exciton Diffusion in Organic Semiconductors. Phys Rev Lett 2016; 116:057402. [PMID: 26894732 DOI: 10.1103/physrevlett.116.057402] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Indexed: 06/05/2023]
Abstract
Exciton diffusion in organic materials provides the operational basis for functioning of such devices as organic solar cells and light-emitting diodes. Here we track the exciton diffusion process in organic semiconductors in real time with a novel technique based on femtosecond photoinduced absorption spectroscopy. Using vacuum-deposited C_{70} layers as a model system, we demonstrate an extremely high diffusion coefficient of D≈3.5×10^{-3} cm^{2}/s that originates from a surprisingly low energetic disorder of <5 meV. The experimental results are well described by the analytical model and supported by extensive Monte Carlo simulations. The proposed noninvasive time-of-flight technique is deemed as a powerful tool for further development of organic optoelectronic components, such as simple layered solar cells, light-emitting diodes, and electrically pumped lasers.
Collapse
Affiliation(s)
- Oleg V Kozlov
- Zernike Institute for Advanced Materials, University of Groningen, 9747AG Groningen, The Netherlands
- Faculty of Physics and International Laser Center, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia
| | - Foppe de Haan
- Zernike Institute for Advanced Materials, University of Groningen, 9747AG Groningen, The Netherlands
| | - Ross A Kerner
- Department of Electrical Engineering and Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, USA
| | - Barry P Rand
- Department of Electrical Engineering and Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, USA
| | | | - Maxim S Pshenichnikov
- Zernike Institute for Advanced Materials, University of Groningen, 9747AG Groningen, The Netherlands
| |
Collapse
|
44
|
Tait JG, Paetzold UW, Cheyns D, Turbiez M, Heremans P, Rand BP. Interfacial Depletion Regions: Beyond the Space Charge Limit in Thick Bulk Heterojunctions. ACS Appl Mater Interfaces 2016; 8:2211-2219. [PMID: 26690662 DOI: 10.1021/acsami.5b10891] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Space charge limited photocurrent is typically described as the limiting factor in carrier extraction efficiency for organic bulk heterojunctions with increasing thickness. It successfully characterizes the carrier extraction efficiency in these devices with thin to moderate thickness and dissimilar carrier mobilities. However, in this article we show that space charge limited photocurrent cannot solely explain the intensity dependent spectral response of extremely thick organic photovoltaics. In addition, interfacial depletion regions near the contacts contribute to the field distribution and carrier collection. Here, we describe charge collection efficiency with an optical p-i-n model, allowing for collection from band bending due to mobility-induced and interfacial-doping-induced space charge regions. We verify the model with up to 1400 nm thick spray-coated devices in both p-i-n (conventional) and n-i-p (inverted) architecture, including variations of thickness, illumination intensity, transport materials, and bifacial (semitransparent) devices.
Collapse
Affiliation(s)
- Jeffrey G Tait
- IMEC , Kapeldreef 75, Leuven B-3001, Belgium
- Department of Electrical Engineering, KULeuven , Kasteelpark Arenberg 10, Leuven B-3001, Belgium
| | | | | | | | - Paul Heremans
- IMEC , Kapeldreef 75, Leuven B-3001, Belgium
- Department of Electrical Engineering, KULeuven , Kasteelpark Arenberg 10, Leuven B-3001, Belgium
| | - Barry P Rand
- Department of Electrical Engineering and Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| |
Collapse
|
45
|
Koh TW, Hiszpanski AM, Sezen M, Naim A, Galfsky T, Trivedi A, Loo YL, Menon V, Rand BP. Metal nanocluster light-emitting devices with suppressed parasitic emission and improved efficiency: exploring the impact of photophysical properties. Nanoscale 2015; 7:9140-9146. [PMID: 25926355 DOI: 10.1039/c5nr01332a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Here we investigate the photophysical properties of Au(0)@Au(i)-thiolate nanoclusters by controlling the degree of aggregation, and measure electrochemical energy levels to design a metal nanocluster-based thin film LED (MNC-LED) structure. These efforts allow us to implement MNC-LEDs with luminance exceeding 40 cd m(-2) and external quantum efficiency exceeding 0.1% with clearly visible orange emission. It is also demonstrated that by varying the sizes of nanoclusters, the electroluminescence spectrum of the device can be tuned to the infrared emission, indicating the possibility of exploiting metal nanocluster emitters for use over a wide spectral range.
Collapse
Affiliation(s)
- T-W Koh
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Tait JG, De Volder MFL, Cheyns D, Heremans P, Rand BP. Absorptive carbon nanotube electrodes: consequences of optical interference loss in thin film solar cells. Nanoscale 2015; 7:7259-7266. [PMID: 25811493 DOI: 10.1039/c5nr01119a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A current bottleneck in the thin film photovoltaic field is the fabrication of low cost electrodes. We demonstrate ultrasonically spray coated multiwalled carbon nanotube (CNT) layers as opaque and absorptive metal-free electrodes deposited at low temperatures and free of post-deposition treatment. The electrodes show sheet resistance as low as 3.4 Ω □(-1), comparable to evaporated metallic contacts deposited in vacuum. Organic photovoltaic devices were optically simulated, showing comparable photocurrent generation between reflective metal and absorptive CNT electrodes for photoactive layer thickness larger than 600 nm when using archetypal poly(3-hexylthiophene) (P3HT) : (6,6)-phenyl C61-butyric acid methyl ester (PCBM) cells. Fabricated devices clearly show that the absorptive CNT electrodes display comparable performance to solution processed and spray coated Ag nanoparticle devices. Additionally, other candidate absorber materials for thin film photovoltaics were simulated with absorptive contacts, elucidating device design in the absence of optical interference and reflection.
Collapse
Affiliation(s)
- Jeffrey G Tait
- Department of Electrical Engineering, KULeuven, Kasteelpark Arenberg 10, Leuven, B-3001 Belgium.
| | | | | | | | | |
Collapse
|
47
|
Kong YL, Tamargo IA, Kim H, Johnson BN, Gupta MK, Koh TW, Chin HA, Steingart DA, Rand BP, McAlpine MC. 3D printed quantum dot light-emitting diodes. Nano Lett 2014; 14:7017-23. [PMID: 25360485 DOI: 10.1021/nl5033292] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Developing the ability to 3D print various classes of materials possessing distinct properties could enable the freeform generation of active electronics in unique functional, interwoven architectures. Achieving seamless integration of diverse materials with 3D printing is a significant challenge that requires overcoming discrepancies in material properties in addition to ensuring that all the materials are compatible with the 3D printing process. To date, 3D printing has been limited to specific plastics, passive conductors, and a few biological materials. Here, we show that diverse classes of materials can be 3D printed and fully integrated into device components with active properties. Specifically, we demonstrate the seamless interweaving of five different materials, including (1) emissive semiconducting inorganic nanoparticles, (2) an elastomeric matrix, (3) organic polymers as charge transport layers, (4) solid and liquid metal leads, and (5) a UV-adhesive transparent substrate layer. As a proof of concept for demonstrating the integrated functionality of these materials, we 3D printed quantum dot-based light-emitting diodes (QD-LEDs) that exhibit pure and tunable color emission properties. By further incorporating the 3D scanning of surface topologies, we demonstrate the ability to conformally print devices onto curvilinear surfaces, such as contact lenses. Finally, we show that novel architectures that are not easily accessed using standard microfabrication techniques can be constructed, by 3D printing a 2 × 2 × 2 cube of encapsulated LEDs, in which every component of the cube and electronics are 3D printed. Overall, these results suggest that 3D printing is more versatile than has been demonstrated to date and is capable of integrating many distinct classes of materials.
Collapse
Affiliation(s)
- Yong Lin Kong
- Department of Mechanical and Aerospace Engineering, Princeton University , Princeton, New Jersey 08544, United States
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Abstract
Light-emitting devices that utilize thin films of metal nanoclusters as quantum emitters are presented. Implementing Ag as well as Au nanoclusters, the versatility of the approach is demonstrated, and it is shown that the electroluminescence measured from these devices is tunable by the choice of nanocluster. Ultimately, it is demonstrated that metal nanoclusters represent an additional option for future light-generating applications.
Collapse
|
49
|
Verreet B, Heremans P, Stesmans A, Rand BP. Microcrystalline organic thin-film solar cells. Adv Mater 2013; 25:5504-5507. [PMID: 23939936 DOI: 10.1002/adma.201301643] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 05/15/2013] [Indexed: 06/02/2023]
Abstract
Microcrystalline organic films with tunable thickness are produced directly on an indium-tin-oxide substrate, by crystallizing a thin amorphous rubrene film followed by its use as a template for subsequent homoepitaxial growth. These films, with exciton diffusion lengths exceeding 200 nm, produce solar cells with increasing photocurrents at thicknesses up to 400 nm with a fill factor >65%, demonstrating significant potential for microcrystalline organic electronic devices.
Collapse
Affiliation(s)
- Bregt Verreet
- imec, Kapeldreef 75, Leuven, B-3001, Belgium; Semiconductor Physics Section, KU Leuven, Celestijnenlaan 200d, Leuven, B-3001, Belgium
| | | | | | | |
Collapse
|
50
|
Vasseur K, Broch K, Ayzner AL, Rand BP, Cheyns D, Frank C, Schreiber F, Toney MF, Froyen L, Heremans P. Controlling the texture and crystallinity of evaporated lead phthalocyanine thin films for near-infrared sensitive solar cells. ACS Appl Mater Interfaces 2013; 5:8505-8515. [PMID: 23905883 DOI: 10.1021/am401933d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
To achieve organic solar cells with a broadened spectral absorption, we aim to promote the growth of the near-infrared (NIR)-active polymorph of lead phthalocyanine (PbPc) on a relevant electrode for solar cell applications. We studied the effect of different substrate modification layers on PbPc thin film structure as a function of thickness and deposition rate (rdep). We characterized crystallinity and orientation by grazing incidence X-ray diffraction (GIXD) and in situ X-ray reflectivity (XRR) and correlated these data to the performance of bilayer solar cells. When deposited onto a self-assembled monolayer (SAM) or a molybdenum oxide (MoO3) buffer layer, the crystallinity of the PbPc films improves with thickness. The transition from a partially crystalline layer close to the substrate to a more crystalline film with a higher content of the NIR-active phase is enhanced at low rdep, thereby leading to solar cells that exhibit a higher maximum in short circuit current density (JSC) for thinner donor layers. The insertion of a CuI layer induces the formation of strongly textured, crystalline PbPc layers with a vertically homogeneous structure. Solar cells based on these templated donor layers show a variation of JSC with thickness that is independent of rdep. Consequently, without decreasing rdep we could achieve JSC=10 mA/cm2, yielding a bilayer solar cell with a peak external quantum efficiency (EQE) of 35% at 900 nm, and an overall power conversion efficiency (PCE) of 2.9%.
Collapse
|