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Chuang CHM, Maurano A, Brandt RE, Hwang GW, Jean J, Buonassisi T, Bulović V, Bawendi MG. Open-circuit voltage deficit, radiative sub-bandgap states, and prospects in quantum dot solar cells. NANO LETTERS 2015; 15:3286-94. [PMID: 25927871 PMCID: PMC4754979 DOI: 10.1021/acs.nanolett.5b00513] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Quantum dot photovoltaics (QDPV) offer the potential for low-cost solar cells. To develop strategies for continued improvement in QDPVs, a better understanding of the factors that limit their performance is essential. Here, we study carrier recombination processes that limit the power conversion efficiency of PbS QDPVs. We demonstrate the presence of radiative sub-bandgap states and sub-bandgap state filling in operating devices by using photoluminescence (PL) and electroluminescence (EL) spectroscopy. These sub-bandgap states are most likely the origin of the high open-circuit-voltage (VOC) deficit and relatively limited carrier collection that have thus far been observed in QDPVs. Combining these results with our perspectives on recent progress in QDPV, we conclude that eliminating sub-bandgap states in PbS QD films has the potential to show a greater gain than may be attainable by optimization of interfaces between QDs and other materials. We suggest possible future directions that could guide the design of high-performance QDPVs.
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Affiliation(s)
- Chia-Hao Marcus Chuang
- Department of Materials Science and Engineering, Cambridge, Massachusetts 02139, United States
| | - Andrea Maurano
- Department of Electrical Engineering and Computer Science, Cambridge, Massachusetts 02139, United States
| | - Riley E. Brandt
- Department of Mechanical Engineering, Massachusetts 02139, United States
| | - Gyu Weon Hwang
- Department of Materials Science and Engineering, Cambridge, Massachusetts 02139, United States
| | - Joel Jean
- Department of Electrical Engineering and Computer Science, Cambridge, Massachusetts 02139, United States
| | - Tonio Buonassisi
- Department of Mechanical Engineering, Massachusetts 02139, United States
| | - Vladimir Bulović
- Department of Electrical Engineering and Computer Science, Cambridge, Massachusetts 02139, United States
| | - Moungi G. Bawendi
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Corresponding Author:
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52
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Wang Y, Yu M, Yang K, Lu J, Chen L. Simple synthesis of luminescent CdSe quantum dots from ascorbic acid and selenium dioxide. LUMINESCENCE 2015; 30:1375-9. [PMID: 25847390 DOI: 10.1002/bio.2909] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 02/26/2015] [Accepted: 02/28/2015] [Indexed: 11/09/2022]
Abstract
A simple, low-cost and convenient method was developed for the synthesis of highly luminescent CdSe quantum dots (QDs) in an aqueous medium. Compared with previous methods, this synthesis was carried out in one pot using ascorbic acid (C6H8O6) to replace NaBH4 or N2H4·H2O as a reductant, and selenium dioxide to replace selenium or its other hazardous, expensive and unstable compounds as a precursor. The mechanism of CdSe QDs formation was elucidated. The influence of various experimental variables, including refluxing time, Cd/MSA and Cd/Se molar ratios, on the luminescent properties of the QDs were systematically investigated. X-Ray powder diffraction and transmission electron microscopy characterization indicated that the QDs had a pure cubic zinc-blended structure with a spherical shape.
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Affiliation(s)
- Yilin Wang
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, Guangxi University, Nanning, 530004, China
| | - Meihua Yu
- Ministry-Province Jointly-Constructed Cultivation Base for the State Key Laboratory of Processing Non-Ferrous Metal and Featured Materials, Guangxi Zhuang Autonomous Region, Guangxi University, Nanning, 530004, China
| | - Kun Yang
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, Guangxi University, Nanning, 530004, China
| | - Jianping Lu
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, Guangxi University, Nanning, 530004, China
| | - Linqing Chen
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, Guangxi University, Nanning, 530004, China
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53
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Malgras V, Nattestad A, Yamauchi Y, Dou SX, Kim JH. The effect of surface passivation on the structure of sulphur-rich PbS colloidal quantum dots for photovoltaic application. NANOSCALE 2015; 7:5706-11. [PMID: 25743947 DOI: 10.1039/c4nr07006b] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The use of PbS colloidal quantum dots in photovoltaic devices is very promising because of their simple and low cost production processes and their unique properties, such as bandgap tunability and potential multiple exciton generation. Here we report the synthesis of PbS nanocrystals used for application in solar cells. The sulphur-rich nature of their surface appears to be caused by the exposure to ambient conditions. The use of methanol as medium during the ligand exchange process has a crucial role in the removal of native oleate ligands. Without proper ligand exchange, the unpassivated surface is subject to ambient hydroxylation leading to the depletion of Pb atoms and the formation of a polysulfide phase. Devices assembled with this material showed good performance with an efficiency of 3.2%.
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Affiliation(s)
- Victor Malgras
- Institute for Superconducting and Electronic Materials (ISEM), University of Wollongong, North Wollongong, NSW 2500, Australia.
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54
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Adinolfi V, Kramer IJ, Labelle AJ, Sutherland BR, Hoogland S, Sargent EH. Photojunction field-effect transistor based on a colloidal quantum dot absorber channel layer. ACS NANO 2015; 9:356-362. [PMID: 25558809 DOI: 10.1021/nn5053537] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The performance of photodetectors is judged via high responsivity, fast speed of response, and low background current. Many previously reported photodetectors based on size-tuned colloidal quantum dots (CQDs) have relied either on photodiodes, which, since they are primary photocarrier devices, lack gain; or photoconductors, which provide gain but at the expense of slow response (due to delayed charge carrier escape from sensitizing centers) and an inherent dark current vs responsivity trade-off. Here we report a photojunction field-effect transistor (photoJFET), which provides gain while breaking prior photoconductors' response/speed/dark current trade-off. This is achieved by ensuring that, in the dark, the channel is fully depleted due to a rectifying junction between a deep-work-function transparent conductive top contact (MoO3) and a moderately n-type CQD film (iodine treated PbS CQDs). We characterize the rectifying behavior of the junction and the linearity of the channel characteristics under illumination, and we observe a 10 μs rise time, a record for a gain-providing, low-dark-current CQD photodetector. We prove, using an analytical model validated using experimental measurements, that for a given response time the device provides a two-orders-of-magnitude improvement in photocurrent-to-dark-current ratio compared to photoconductors. The photoJFET, which relies on a junction gate-effect, enriches the growing family of CQD photosensitive transistors.
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Affiliation(s)
- Valerio Adinolfi
- Department of Electrical Engineering and Computer Science, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
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55
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A quantitative model for charge carrier transport, trapping and recombination in nanocrystal-based solar cells. Nat Commun 2015; 6:6180. [PMID: 25625647 PMCID: PMC4317500 DOI: 10.1038/ncomms7180] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 12/27/2014] [Indexed: 12/23/2022] Open
Abstract
Improving devices incorporating solution-processed nanocrystal-based semiconductors requires a better understanding of charge transport in these complex, inorganic–organic materials. Here we perform a systematic study on PbS nanocrystal-based diodes using temperature-dependent current–voltage characterization and thermal admittance spectroscopy to develop a model for charge transport that is applicable to different nanocrystal-solids and device architectures. Our analysis confirms that charge transport occurs in states that derive from the quantum-confined electronic levels of the individual nanocrystals and is governed by diffusion-controlled trap-assisted recombination. The current is limited not by the Schottky effect, but by Fermi-level pinning because of trap states that is independent of the electrode–nanocrystal interface. Our model successfully explains the non-trivial trends in charge transport as a function of nanocrystal size and the origins of the trade-offs facing the optimization of nanocrystal-based solar cells. We use the insights from our charge transport model to formulate design guidelines for engineering higher-performance nanocrystal-based devices. Colloidal nanocrystals could help improve the performance of the next generation of solar cells, but a model that fully describes the electronic behaviour of such devices is missing. Bozyigit et al. now develop a quantitative model for charge transport in these solar cells.
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56
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57
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Eita M, Usman A, El-Ballouli AO, Alarousu E, Bakr OM, Mohammed OF. A layer-by-layer ZnO nanoparticle-PbS quantum dot self-assembly platform for ultrafast interfacial electron injection. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:112-118. [PMID: 25163799 DOI: 10.1002/smll.201400939] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Indexed: 06/03/2023]
Abstract
Absorbent layers of semiconductor quantum dots (QDs) are now used as material platforms for low-cost, high-performance solar cells. The semiconductor metal oxide nanoparticles as an acceptor layer have become an integral part of the next generation solar cell. To achieve sufficient electron transfer and subsequently high conversion efficiency in these solar cells, however, energy-level alignment and interfacial contact between the donor and the acceptor units are needed. Here, the layer-by-layer (LbL) technique is used to assemble ZnO nanoparticles (NPs), providing adequate PbS QD uptake to achieve greater interfacial contact compared with traditional sputtering methods. Electron injection at the PbS QD and ZnO NP interface is investigated using broadband transient absorption spectroscopy with 120 femtosecond temporal resolution. The results indicate that electron injection from photoexcited PbS QDs to ZnO NPs occurs on a time scale of a few hundred femtoseconds. This observation is supported by the interfacial electronic-energy alignment between the donor and acceptor moieties. Finally, due to the combination of large interfacial contact and ultrafast electron injection, this proposed platform of assembled thin films holds promise for a variety of solar cell architectures and other settings that principally rely on interfacial contact, such as photocatalysis.
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Affiliation(s)
- Mohamed Eita
- Solar and Photovoltaics Engineering Research Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Kingdom of Saudi Arabia
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58
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Kim MR, Ma D. Quantum-Dot-Based Solar Cells: Recent Advances, Strategies, and Challenges. J Phys Chem Lett 2015; 6:85-99. [PMID: 26263096 DOI: 10.1021/jz502227h] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Among next-generation photovoltaic systems requiring low cost and high efficiency, quantum dot (QD)-based solar cells stand out as a very promising candidate because of the unique and versatile characteristics of QDs. The past decade has already seen rapid conceptual and technological advances on various aspects of QD solar cells, and diverse opportunities, which QDs can offer, predict that there is still ample room for further development and breakthroughs. In this Perspective, we first review the attractive advantages of QDs, such as size-tunable band gaps and multiple exciton generation (MEG), beneficial to solar cell applications. We then analyze major strategies, which have been extensively explored and have largely contributed to the most recent and significant achievements in QD solar cells. Finally, their high potential and challenges are discussed. In particular, QD solar cells are considered to hold immense potential to overcome the theoretical efficiency limit of 31% for single-junction cells.
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Affiliation(s)
- Mee Rahn Kim
- Centre-Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
| | - Dongling Ma
- Centre-Énergie, Matériaux et Télécommunications, Institut National de la Recherche Scientifique, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada
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59
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Yang Y, Zhao B, Gao Y, Liu H, Tian Y, Qin D, Wu H, Huang W, Hou L. Novel Hybrid Ligands for Passivating PbS Colloidal Quantum Dots to Enhance the Performance of Solar Cells. NANO-MICRO LETTERS 2015; 7:325-331. [PMID: 30464978 PMCID: PMC6223900 DOI: 10.1007/s40820-015-0046-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Accepted: 05/30/2015] [Indexed: 05/14/2023]
Abstract
We developed novel hybrid ligands to passivate PbS colloidal quantum dots (CQDs), and two kinds of solar cells based on as-synthesized CQDs were fabricated to verify the passivation effects of the ligands. It was found that the ligands strongly affected the optical and electrical properties of CQDs, and the performances of solar cells were enhanced strongly. The optimized hybrid ligands, oleic amine/octyl-phosphine acid/CdCl2 improved power conversion efficiency (PCE) to much higher of 3.72 % for Schottky diode cell and 5.04 % for p-n junction cell. These results may be beneficial to design passivation strategy for low-cost and high-performance CQDs solar cells.
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Affiliation(s)
- Yuehua Yang
- State Key Laboratory of Luminescent Materials & Devices, Institute of Polymer Optoelectronic Materials & Devices, South China University of Technology, Guangzhou, 510640 People’s Republic of China
| | - Baofeng Zhao
- State Key Laboratory of Luminescent Materials & Devices, Institute of Polymer Optoelectronic Materials & Devices, South China University of Technology, Guangzhou, 510640 People’s Republic of China
| | - Yuping Gao
- State Key Laboratory of Luminescent Materials & Devices, Institute of Polymer Optoelectronic Materials & Devices, South China University of Technology, Guangzhou, 510640 People’s Republic of China
| | - Han Liu
- State Key Laboratory of Luminescent Materials & Devices, Institute of Polymer Optoelectronic Materials & Devices, South China University of Technology, Guangzhou, 510640 People’s Republic of China
| | - Yiyao Tian
- State Key Laboratory of Luminescent Materials & Devices, Institute of Polymer Optoelectronic Materials & Devices, South China University of Technology, Guangzhou, 510640 People’s Republic of China
| | - Donghuan Qin
- State Key Laboratory of Luminescent Materials & Devices, Institute of Polymer Optoelectronic Materials & Devices, South China University of Technology, Guangzhou, 510640 People’s Republic of China
| | - Hongbin Wu
- State Key Laboratory of Luminescent Materials & Devices, Institute of Polymer Optoelectronic Materials & Devices, South China University of Technology, Guangzhou, 510640 People’s Republic of China
| | - Wenbo Huang
- State Key Laboratory of Luminescent Materials & Devices, Institute of Polymer Optoelectronic Materials & Devices, South China University of Technology, Guangzhou, 510640 People’s Republic of China
| | - Lintao Hou
- Siyuan Laboratory, Department of Physics, Jinan University, Guangzhou, 510632 People’s Republic of China
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60
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Wan Y, Han M, Yu L, Jia J, Yi G. Fabrication and photoelectrochemical properties of TiO2/CuInS2/Bi2S3 core/shell/shell nanorods electrodes. RSC Adv 2015. [DOI: 10.1039/c5ra14548a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The FESEM images (a and b), photocurrent density versus potential (c–v) curves (c) and schematic of the energy level arrangement (d).
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Affiliation(s)
- Yanling Wan
- State Key Laboratory of Solid Lubrication
- Lanzhou Institute of Chemical Physics
- Chinese Academy of Sciences
- Lanzhou
- PR China
| | - Minmin Han
- State Key Laboratory of Solid Lubrication
- Lanzhou Institute of Chemical Physics
- Chinese Academy of Sciences
- Lanzhou
- PR China
| | - Limin Yu
- State Key Laboratory of Solid Lubrication
- Lanzhou Institute of Chemical Physics
- Chinese Academy of Sciences
- Lanzhou
- PR China
| | - Junhong Jia
- State Key Laboratory of Solid Lubrication
- Lanzhou Institute of Chemical Physics
- Chinese Academy of Sciences
- Lanzhou
- PR China
| | - Gewen Yi
- State Key Laboratory of Solid Lubrication
- Lanzhou Institute of Chemical Physics
- Chinese Academy of Sciences
- Lanzhou
- PR China
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61
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Gao J, Zhang J, van de Lagemaat J, Johnson JC, Beard MC. Charge generation in PbS quantum dot solar cells characterized by temperature-dependent steady-state photoluminescence. ACS NANO 2014; 8:12814-12825. [PMID: 25485555 DOI: 10.1021/nn506075s] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Charge-carrier generation and transport within PbS quantum dot (QD) solar cells is investigated by measuring the temperature-dependent steady-state photoluminescence (PL) concurrently during in situ current-voltage characterization. We first compare the temperature-dependent PL quenching for PbS QD films where the PbS QDs retain their original oleate ligand to that of PbS QDs treated with 1,2-ethanedithiol (EDT), producing a conductive QD layer, either on top of glass or on a ZnO nanocrystal film. We then measure and analyze the temperature-dependent PL in a completed QD-PV architecture with the structure Al/MoO3/EDT-PbS/ZnO/ITO/glass, collecting the PL and the current simultaneously. We find that at low temperatures excitons diffuse to the ZnO interface, where PL is quenched via interfacial charge transfer. At high temperatures, excitons dissociate in the bulk of the PbS QD film via phonon-assisted tunneling to nearby QDs, and that dissociation is in competition with the intrinsic radiative and nonradiative rates of the individual QDs. The activation energy for exciton dissociation in the QD-PV devices is found to be ∼40 meV, which is considerably lower than that of the electrodeless samples, and suggests unique interactions between injected and photogenerated carriers in devices.
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Affiliation(s)
- Jianbo Gao
- Center for Advanced Solar Photophysics, National Renewable Energy Laboratory , Golden, Colorado 80401, United States
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62
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Oh SJ, Wang Z, Berry NE, Choi JH, Zhao T, Gaulding EA, Paik T, Lai Y, Murray CB, Kagan CR. Engineering charge injection and charge transport for high performance PbSe nanocrystal thin film devices and circuits. NANO LETTERS 2014; 14:6210-6. [PMID: 25298154 DOI: 10.1021/nl502491d] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We study charge injection and transport in PbSe nanocrystal thin films. By engineering the contact metallurgy and nanocrystal ligand exchange chemistry and surface passivation, we demonstrate partial Fermi-level pinning at the metal-nanocrystal interface and an insulator-to-metal transition with increased coupling and doping, allowing us to design high conductivity and mobility PbSe nanocrystal films. We construct complementary nanocrystal circuits from n-type and p-type transistors realized from a single nanocrystal material by selecting the contact metallurgy.
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Affiliation(s)
- Soong Ju Oh
- Department of Materials Science and Engineering, ‡Department of Electrical and Systems Engineering, and §Department of Chemistry, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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63
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Chuang CHM, Brown PR, Bulović V, Bawendi MG. Improved performance and stability in quantum dot solar cells through band alignment engineering. NATURE MATERIALS 2014; 13:796-801. [PMID: 24859641 PMCID: PMC4110173 DOI: 10.1038/nmat3984] [Citation(s) in RCA: 644] [Impact Index Per Article: 64.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 04/15/2014] [Indexed: 05/19/2023]
Abstract
Solution processing is a promising route for the realization of low-cost, large-area, flexible and lightweight photovoltaic devices with short energy payback time and high specific power. However, solar cells based on solution-processed organic, inorganic and hybrid materials reported thus far generally suffer from poor air stability, require an inert-atmosphere processing environment or necessitate high-temperature processing, all of which increase manufacturing complexities and costs. Simultaneously fulfilling the goals of high efficiency, low-temperature fabrication conditions and good atmospheric stability remains a major technical challenge, which may be addressed, as we demonstrate here, with the development of room-temperature solution-processed ZnO/PbS quantum dot solar cells. By engineering the band alignment of the quantum dot layers through the use of different ligand treatments, a certified efficiency of 8.55% has been reached. Furthermore, the performance of unencapsulated devices remains unchanged for over 150 days of storage in air. This material system introduces a new approach towards the goal of high-performance air-stable solar cells compatible with simple solution processes and deposition on flexible substrates.
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Affiliation(s)
- Chia-Hao M. Chuang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United States
| | - Patrick R. Brown
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United States
| | - Vladimir Bulović
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United States
| | - Moungi G. Bawendi
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, United States
- Correspondence and requests for materials should be addressed to M.G.B. ()
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64
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Rath AK, Pelayo Garcia de Arquer F, Stavrinadis A, Lasanta T, Bernechea M, Diedenhofen SL, Konstantatos G. Remote trap passivation in colloidal quantum dot bulk nano-heterojunctions and its effect in solution-processed solar cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:4741-7. [PMID: 24895324 DOI: 10.1002/adma.201400297] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/28/2014] [Indexed: 05/05/2023]
Abstract
More-efficient charge collection and suppressed trap recombination in colloidal quantum dot (CQD) solar cells is achieved by means of a bulk nano-heterojunction (BNH) structure, in which p-type and n-type materials are blended on the nanometer scale. The improved performance of the BNH devices, compared with that of bilayer devices, is displayed in higher photocurrents and higher open-circuit voltages (resulting from a trap passivation mechanism).
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Affiliation(s)
- Arup K Rath
- ICFO - Institut de Ciéncies Fotóniques, Mediterranean Technology Park, Av. Carl Friedrich Gauss, 3, 08860, Castelldefels, Barcelona, Spain; CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411008, India
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65
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Brown PR, Kim D, Lunt RR, Zhao N, Bawendi MG, Grossman JC, Bulović V. Energy level modification in lead sulfide quantum dot thin films through ligand exchange. ACS NANO 2014; 8:5863-72. [PMID: 24824726 DOI: 10.1021/nn500897c] [Citation(s) in RCA: 399] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The electronic properties of colloidal quantum dots (QDs) are critically dependent on both QD size and surface chemistry. Modification of quantum confinement provides control of the QD bandgap, while ligand-induced surface dipoles present a hitherto underutilized means of control over the absolute energy levels of QDs within electronic devices. Here, we show that the energy levels of lead sulfide QDs, measured by ultraviolet photoelectron spectroscopy, shift by up to 0.9 eV between different chemical ligand treatments. The directions of these energy shifts match the results of atomistic density functional theory simulations and scale with the ligand dipole moment. Trends in the performance of photovoltaic devices employing ligand-modified QD films are consistent with the measured energy level shifts. These results identify surface-chemistry-mediated energy level shifts as a means of predictably controlling the electronic properties of colloidal QD films and as a versatile adjustable parameter in the performance optimization of QD optoelectronic devices.
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Affiliation(s)
- Patrick R Brown
- Department of Physics, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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66
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Yang Y, Lian T. Multiple exciton dissociation and hot electron extraction by ultrafast interfacial electron transfer from PbS QDs. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2013.11.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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67
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Yoon W, Boercker JE, Lumb MP, Placencia D, Foos EE, Tischler JG. Enhanced open-circuit voltage of PbS nanocrystal quantum dot solar cells. Sci Rep 2014; 3:2225. [PMID: 23868514 PMCID: PMC3715763 DOI: 10.1038/srep02225] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 06/24/2013] [Indexed: 02/06/2023] Open
Abstract
Nanocrystal quantum dots (QD) show great promise toward improving solar cell efficiencies through the use of quantum confinement to tune absorbance across the solar spectrum and enable multi-exciton generation. Despite this remarkable potential for high photocurrent generation, the achievable open-circuit voltage (Voc) is fundamentally limited due to non-radiative recombination processes in QD solar cells. Here we report the highest open-circuit voltages to date for colloidal QD based solar cells under one sun illumination. This Voc of 692 ± 7 mV for 1.4 eV PbS QDs is a result of improved passivation of the defective QD surface, demonstrating Voc(mV)=553Eg/q-59 as a function of the QD bandgap (Eg). Comparing experimental Voc variation with the theoretical upper-limit obtained from one diode modeling of the cells with different Eg, these results clearly demonstrate that there is a tremendous opportunity for improvement of Voc to values greater than 1 V by using smaller QDs in QD solar cells.
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Affiliation(s)
- Woojun Yoon
- U.S. Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375, United States.
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68
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Chen Y, Tao Q, Fu W, Yang H, Zhou X, Zhang Y, Su S, Wang P, Li M. Enhanced solar cell efficiency and stability using ZnS passivation layer for CdS quantum-dot sensitized actinomorphic hexagonal columnar ZnO. Electrochim Acta 2014. [DOI: 10.1016/j.electacta.2013.10.081] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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69
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Zhang J, Gao J, Miller EM, Luther JM, Beard MC. Diffusion-controlled synthesis of PbS and PbSe quantum dots with in situ halide passivation for quantum dot solar cells. ACS NANO 2014; 8:614-22. [PMID: 24341705 DOI: 10.1021/nn405236k] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We developed a simple non-hot-injection synthetic route that achieves in situ halide-passivated PbS and PbSe quantum dots (QDs) and simplifies the fabrication of Pb-chalcogenide QD solar cells. The synthesis mechanism follows a temperature-dependent diffusion growth model leading to strategies that can achieve narrow size distributions for a range of sizes. We show that PbS QDs can be produced with a diameter as small as 2.2 nm, corresponding to a 1.7 eV band gap, while the resulting size distribution (6-7%) is comparable to that of hot-injection syntheses. The in situ chloride surface passivation is demonstrated by X-ray photoelectron spectroscopy and an improved photostability of both PbS and PbSe QDs when stored under air. Additionally, the photoluminescence quantum yield of the PbS QDs is ∼30% higher compared to the traditional synthesis. We show that PbS QD solar cells with 6.5% power conversion efficiency (PCE) can be constructed. Finally, we fabricated PbSe QD solar cells in air (rather than in inert atmosphere), achieving a PCE of 2.65% using relatively large QDs with a corresponding band gap of 0.89 eV.
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Affiliation(s)
- Jianbing Zhang
- School of Optical and Electronic Information, Huazhong University of Science and Technology , 1037 Luoyu Road, Wuhan, Hubei 430074, China
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70
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Sun M, Fu W, Li Q, Yin G, Chi K, Ma J, Yang L, Mu Y, Chen Y, Su S, Zhang W, Yang H. Embedded CdS nanorod arrays in PbS absorber layers: enhanced energy conversion efficiency in bulk heterojunction solar cells. RSC Adv 2014. [DOI: 10.1039/c3ra45446k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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71
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Bose R, Manna G, Jana S, Pradhan N. Ag2S–AgInS2: p–n junction heteronanostructures with quasi type-II band alignment. Chem Commun (Camb) 2014; 50:3074-7. [DOI: 10.1039/c3cc48903e] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A single nanostructure p–n junction diode has been fabricated colloidally by synthesizing a heterostructure comprising of p-type Ag2S and n-type AgInS2, where the quasi type-II band alignment of the constituents further improve charge separation.
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Affiliation(s)
- Riya Bose
- Centre for Advanced Materials and Department of Materials Science
- Indian Association for the Cultivation of Science
- Kolkata 700032, India
| | - Goutam Manna
- Centre for Advanced Materials and Department of Materials Science
- Indian Association for the Cultivation of Science
- Kolkata 700032, India
| | - Santanu Jana
- Centre for Advanced Materials and Department of Materials Science
- Indian Association for the Cultivation of Science
- Kolkata 700032, India
| | - Narayan Pradhan
- Centre for Advanced Materials and Department of Materials Science
- Indian Association for the Cultivation of Science
- Kolkata 700032, India
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72
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Hyun BR, Choi JJ, Seyler KL, Hanrath T, Wise FW. Heterojunction PbS nanocrystal solar cells with oxide charge-transport layers. ACS NANO 2013; 7:10938-10947. [PMID: 24274761 DOI: 10.1021/nn404457c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Oxides are commonly employed as electron-transport layers in optoelectronic devices based on semiconductor nanocrystals, but are relatively rare as hole-transport layers. We report studies of NiO hole-transport layers in PbS nanocrystal photovoltaic structures. Transient fluorescence experiments are used to verify the relevant energy levels for hole transfer. On the basis of these results, planar heterojunction devices with ZnO as the photoanode and NiO as the photocathode were fabricated and characterized. Solution-processed devices were used to systematically study the dependence on nanocrystal size and achieve conversion efficiency as high as 2.5%. Optical modeling indicates that optimum performance should be obtained with thinner oxide layers than can be produced reliably by solution casting. Room-temperature sputtering allows deposition of oxide layers as thin as 10 nm, which enables optimization of device performance with respect to the thickness of the charge-transport layers. The best devices achieve an open-circuit voltage of 0.72 V and efficiency of 5.3% while eliminating most organic material from the structure and being compatible with tandem structures.
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Affiliation(s)
- Byung-Ryool Hyun
- School of Applied and Engineering Physics and ‡School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States
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73
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Barpuzary D, Qureshi M. Enhanced photovoltaic performance of semiconductor-sensitized ZnO-CdS coupled with graphene oxide as a novel photoactive material. ACS APPLIED MATERIALS & INTERFACES 2013; 5:11673-82. [PMID: 24152060 DOI: 10.1021/am403268w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We report, for the first time, a ternary hybrid composite of ZnO, CdS, and graphene oxide (GO) as a one-coat paintable solution in performing the role of a photoanode for the semiconductor-sensitized solar cell, wherein hierarchical ZnO-CdS heteroarrays are embedded onto the GO sheets. The photoconversion properties of the hybrid ternary-system-based photoanodes are evaluated in the photovoltaic devices having Pt and Ag as the counter electrodes with sulfide/polysulfide redox couple as the electrolyte. Power conversion efficiency (PCE) of ~2.82% has been achieved with a short-circuit current density (Jsc) of ~7.3 mA/cm(2), a maximum open-circuit voltage (Voc) of 703 mV, and a fill factor (FF) of 54% for the photovoltaic cell with Pt as a counter electrode. The identical hybrid photoanode against the Ag counter electrode resulted in the following values: PCE ≈ 1.96%, Jsc ≈ 5.7 mA/cm(2), Voc ≈ 565 mV, and 63% FF. The band position proximity of CdS, ZnO, and GO in the proposed ternary system facilitates an efficient electronic interactions thereby promoting the electron transport within CdS-ZnO-GO. The hierarchically grown CdS nanorods over ZnO nanoparticle act as the sensitizer for ZnO, enhancing the visible light harvesting ability. The loading of 1.0 wt% of GO to ZnO-CdS results in enhanced separation of photogenerated electrons and holes within the photoactive layer, thereby improving the photovoltaic performance. The electronic interactions of GO to ZnO-CdS is evident from the drastic quenching of fluorescence, reduced exciton lifetime and Raman scattering measurements. In order to study the effect of GO in the photovoltaic performance, we have compared our result with the photoelectrical parameters of the devices fabricated using the binary ZnO-CdS composite as GO-free photoanodes.
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Affiliation(s)
- Dipankar Barpuzary
- Materials Science Laboratory, Department of Chemistry, Indian Institute of Technology Guwahati , Assam-781039, India
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74
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Yuan M, Zhitomirsky D, Adinolfi V, Voznyy O, Kemp KW, Ning Z, Lan X, Xu J, Kim JY, Dong H, Sargent EH. Doping control via molecularly engineered surface ligand coordination. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:5586-92. [PMID: 23913360 DOI: 10.1002/adma201302802] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Indexed: 05/15/2023]
Abstract
A means to control the net doping of a CQD solid is identified via the design of the bidentate ligand crosslinking the material. The strategy does not rely on implementing different atmospheres at different steps in device processing, but instead is a robust strategy implemented in a single processing ambient. We achieve an order of magnitude difference in doping that allows us to build a graded photovoltaic device and maintain high current and voltage at maximum power-point conditions.
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Affiliation(s)
- Mingjian Yuan
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
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75
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Kramer IJ, Sargent EH. The Architecture of Colloidal Quantum Dot Solar Cells: Materials to Devices. Chem Rev 2013; 114:863-82. [DOI: 10.1021/cr400299t] [Citation(s) in RCA: 401] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Illan J. Kramer
- Edward S. Rogers Department of Electrical & Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario M5S 3G4, Canada
| | - Edward H. Sargent
- Edward S. Rogers Department of Electrical & Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario M5S 3G4, Canada
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76
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Ye J, Sun L, Gao S. Fabrication of hollow PbS nanospheres and application in phenol release. SPRINGERPLUS 2013; 2:323. [PMID: 23961397 PMCID: PMC3733068 DOI: 10.1186/2193-1801-2-323] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 04/25/2013] [Indexed: 11/15/2022]
Abstract
This article demonstrates a versatile method to prepare the hollow PbS nanospheres via the template method. First, the latex poly (vinyl benzyl chloride) (PVBC) nanoparticles were synthesized by the radical polymerization, followed by the atom transfer reversible polymerization of lead (II) dimethacrylate (Pb (MA)2) on the surfaces of the latex nanoparticles. Then, the ethanethioamide was reacted with the nanoparticles to afford the PbS. By calcination at 600°C for 6 h, the template was removed to obtain the hollow PbS nanospheres. The structure, morphology and optical properties of the hollow PbS nanospheres were carefully investigated. The received hollow PbS nanospheres could be used for the controlled release of phenol after absorbing phenol solution.
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Affiliation(s)
- Jian Ye
- Department of Chemical and Environmental Engineering, Bengbu College, Bengbu, 233030 China
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77
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Chen G, Seo J, Yang C, Prasad PN. Nanochemistry and nanomaterials for photovoltaics. Chem Soc Rev 2013; 42:8304-38. [PMID: 23868557 DOI: 10.1039/c3cs60054h] [Citation(s) in RCA: 229] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Nanochemistry and nanomaterials provide numerous opportunities for a new generation of photovoltaics with high solar energy conversion efficiencies at low fabrication cost. Quantum-confined nanomaterials and polymer-inorganic nanocomposites can be tailored to harvest sun light over a broad range of the spectrum, while plasmonic structures offer effective ways to reduce the thickness of light-absorbing layers. Multiple exciton generation, singlet exciton fission, photon down-conversion, and photon up-conversion realized in nanostructures, create significant interest for harvesting underutilized ultraviolet and currently unutilized infrared photons. Nanochemical interface engineering of nanoparticle surfaces and junction-interfaces enable enhanced charge separation and collection. In this review, we survey these recent advances employed to introduce new concepts for improving the solar energy conversion efficiency, and reduce the device fabrication cost in photovoltaic technologies. The review concludes with a summary of contributions already made by nanochemistry. It then describes the challenges and opportunities in photovoltaics where the chemical community can play a vital role.
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Affiliation(s)
- Guanying Chen
- School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin, Heilongjiang 150001, People's Republic of China.
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78
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79
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Zhou R, Stalder R, Xie D, Cao W, Zheng Y, Yang Y, Plaisant M, Holloway PH, Schanze KS, Reynolds JR, Xue J. Enhancing the efficiency of solution-processed polymer:colloidal nanocrystal hybrid photovoltaic cells using ethanedithiol treatment. ACS NANO 2013; 7:4846-4854. [PMID: 23668301 DOI: 10.1021/nn305823w] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Advances in colloidal inorganic nanocrystal synthesis and processing have led to the demonstration of organic-inorganic hybrid photovoltaic (PV) cells using low-cost solution processes from blends of conjugated polymer and colloidal nanocrystals. However, the performance of such hybrid PV cells has been limited due to the lack of control at the complex interfaces between the organic and inorganic hybrid active materials. Here we show that the efficiency of hybrid PV devices can be significantly enhanced by engineering the polymer-nanocrystal interface with proper chemical treatment. Using two different conjugated polymers, poly(3-hexylthiophene) (P3HT) and poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT), we show that treating the polymer:nanocrystal hybrid film in an ethanedithiol-containing acetonitrile solution can increase the efficiency of the hybrid PV devices by 30-90%, and a maximum power conversion efficiency of 5.2 ± 0.3% was obtained in the PCPDTBT:CdSe devices at 0.2 sun (AM 1.5G), which was slightly reduced to 4.7 ± 0.3% at 1 sun. The ethanedithiol treatment did not result in significant changes in the morphology and UV-vis optical absorption of the hybrid thin films; however, infrared absorption, NMR, and X-ray photoelectron spectroscopies revealed the effective removal of organic ligands, especially the charged phosphonic acid ligands, from the CdSe nanorod surface after the treatment, accompanied by the possible monolayer passivation of nanorod surfaces with Cd-thiolates. We attribute the hybrid PV cell efficiency increase upon the ethanedithiol treatment to the reduction in charge and exciton recombination sites on the nanocrystal surface and the simultaneous increase in electron transport through the hybrid film.
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Affiliation(s)
- Renjia Zhou
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611-6400, USA
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80
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Ehrler B, Musselman KP, Böhm ML, Morgenstern FSF, Vaynzof Y, Walker BJ, Macmanus-Driscoll JL, Greenham NC. Preventing interfacial recombination in colloidal quantum dot solar cells by doping the metal oxide. ACS NANO 2013; 7:4210-20. [PMID: 23531107 DOI: 10.1021/nn400656n] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Recent research has pushed the efficiency of colloidal quantum dot solar cells toward a level that spurs commercial interest. Quantum dot/metal oxide bilayers form the most efficient colloidal quantum dot solar cells, and most studies have advanced the understanding of the quantum dot component. We study the interfacial recombination process in depleted heterojunction colloidal quantum dot (QD) solar cells formed with ZnO as the oxide by varying (i) the carrier concentration of the ZnO layer and (ii) the density of intragap recombination sites in the QD layer. We find that the open-circuit voltage and efficiency of PbS QD/ZnO devices can be improved by 50% upon doping of the ZnO with nitrogen to reduce its carrier concentration. In contrast, doping the ZnO did not change the performance of PbSe QD/ZnO solar cells. We use X-ray photoemission spectroscopy, ultraviolet photoemission spectroscopy, transient photovoltage decay measurements, transient absorption spectroscopy, and intensity-dependent photocurrent measurements to investigate the origin of this effect. We find a significant density of intragap states within the band gap of the PbS quantum dots. These states facilitate recombination at the PbS/ZnO interface, which can be suppressed by reducing the density of occupied states in the ZnO. For the PbSe QD/ZnO solar cells, where fewer intragap states are observed in the quantum dots, the interfacial recombination channel does not limit device performance. Our study sheds light on the mechanisms of interfacial recombination in colloidal quantum dot solar cells and emphasizes the influence of quantum dot intragap states and metal oxide properties on this loss pathway.
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Affiliation(s)
- Bruno Ehrler
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK
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81
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Woo JY, Lee J, Lee H, Lee N, Oh JH, Do YR, Han CS. Visible cathodoluminescence of quantum dot films by direct irradiation of electron beam and its materialization as a field emission device. OPTICS EXPRESS 2013; 21:12519-12526. [PMID: 23736470 DOI: 10.1364/oe.21.012519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The field emission (FE) device based on quantum dot (QD) films as a cathodoluminescent (CL) material has not emerged yet due to the relatively low quantum efficiency and weak photostability of nanocrystals (NCs). Here we improve film stability and luminescence yields by preparing neat films of well-packed core-multishell QDs using spray coating method and then using low-temperature atomic layer deposition (ALD) to infill the pores of these films with metal oxides to produce inorganic nanocomposites. The ALD coatings to protect oxidation and degradation by electrons prevent internal atomic and molecular diffusion and decrease surface trap densities of QD films. Furthermore, the CL of the core-multishell QD films is 2.4 times higher than before ALD infilling. We fabricate the FE device by combining cathode structure with carbon nanotube (CNT) emitters and anode plates with QD thin film and successfully can get brilliant images of the light-emitting FE device. Our research opens a way for developing new quantum optoelectronics with high-performance.
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Affiliation(s)
- Ju Yeon Woo
- 1School of Mechanical Engineering, Korea University, Seoul 136713, South Korea
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82
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Schouteden K, Zeng YJ, Lauwaet K, Romero CP, Goris B, Bals S, Van Tendeloo G, Lievens P, Van Haesendonck C. Band structure quantization in nanometer sized ZnO clusters. NANOSCALE 2013; 5:3757-3763. [PMID: 23515535 DOI: 10.1039/c3nr33989k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Nanometer sized ZnO clusters are produced in the gas phase and subsequently deposited on clean Au(111) surfaces under ultra-high vacuum conditions. The zinc blende atomic structure of the approximately spherical ZnO clusters is resolved by high resolution scanning transmission electron microscopy. The large band gap and weak n-type conductivity of individual clusters are determined by scanning tunnelling microscopy and spectroscopy at cryogenic temperatures. The conduction band is found to exhibit clear quantization into discrete energy levels, which can be related to finite-size effects reflecting the zero-dimensional confinement. Our findings illustrate that gas phase cluster production may provide unique possibilities for the controlled fabrication of high purity quantum dots and heterostructures that can be size selected prior to deposition on the desired substrate under controlled ultra-high vacuum conditions.
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Affiliation(s)
- Koen Schouteden
- Laboratory of Solid-State Physics and Magnetism, KU Leuven, Celestijnenlaan 200d-box 2414, BE-3001 Leuven, Belgium.
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83
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Bozyigit D, Jakob M, Yarema O, Wood V. Deep level transient spectroscopy (DLTS) on colloidal-synthesized nanocrystal solids. ACS APPLIED MATERIALS & INTERFACES 2013; 5:2915-2919. [PMID: 23527751 DOI: 10.1021/am400326t] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We demonstrate current-based, deep level transient spectroscopy (DLTS) on semiconductor nanocrystal solids to obtain quantitative information on deep-lying trap states, which play an important role in the electronic transport properties of these novel solids and impact optoelectronic device performance. Here, we apply this purely electrical measurement to an ethanedithiol-treated, PbS nanocrystal solid and find a deep trap with an activation energy of 0.40 eV and a density of NT = 1.7 × 10(17) cm(-3). We use these findings to draw and interpret band structure models to gain insight into charge transport in PbS nanocrystal solids and the operation of PbS nanocrystal-based solar cells.
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Affiliation(s)
- Deniz Bozyigit
- Laboratory for Nanoelectronics, Department of Information Technology and Electrical Engineering, Eidgenoessische Technische Hochschule Zurich
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84
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Boehme SC, Wang H, Siebbeles LDA, Vanmaekelbergh D, Houtepen AJ. Electrochemical charging of CdSe quantum dot films: dependence on void size and counterion proximity. ACS NANO 2013; 7:2500-8. [PMID: 23398747 DOI: 10.1021/nn3058455] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Films of colloidal quantum dots (QDs) show great promise for application in optoelectronic devices. Great advances have been made in recent years in designing efficient QD solar cells and LEDs. A very important aspect in the design of devices based on QD films is the knowledge of their absolute energy levels. Unfortunately, reported energy levels vary markedly depending on the employed measurement technique and the environment of the sample. In this report, we determine absolute energy levels of QD films by electrochemical charge injection. The concomitant change in optical absorption of the film allows quantification of the number of charges in quantum-confined levels and thereby their energetic position. We show here that the size of voids in the QD films (i.e., the space between the quantum dots) determines the amount of charges that may be injected into the films. This effect is attributed to size exclusion of countercharges from the electrolyte solution. Further, the energy of the QD levels depends on subtle changes in the QD film and the supporting electrolyte: the size of the cation and the QD ligand length. These nontrivial effects can be explained by the proximity of the cation to the QD surface and a concomitant lowering of the electrochemical potential. Our findings help explain the wide range of reported values for QD energy levels and redefine the limit of applicability of electrochemical measurements on QD films. Finally, the finding that the energy of QD levels depends on ligand length and counterion size may be exploited in optimized designs of QD sensitized solar cells.
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Affiliation(s)
- Simon C Boehme
- Chemical Engineering, Optoelectronic Materials, TU Delft, Julianalaan 136, 2628 BL Delft, The Netherlands
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85
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Chang LY, Lunt RR, Brown PR, Bulović V, Bawendi MG. Low-temperature solution-processed solar cells based on PbS colloidal quantum dot/CdS heterojunctions. NANO LETTERS 2013; 13:994-9. [PMID: 23406331 DOI: 10.1021/nl3041417] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
PbS colloidal quantum dot heterojunction solar cells have shown significant improvements in performance, mostly based on devices that use high-temperature annealed transition metal oxides to create rectifying junctions with quantum dot thin films. Here, we demonstrate a solar cell based on the heterojunction formed between PbS colloidal quantum dot layers and CdS thin films that are deposited via a solution process at 80 °C. The resultant device, employing a 1,2-ethanedithiol ligand exchange scheme, exhibits an average power conversion efficiency of 3.5%. Through a combination of thickness-dependent current density-voltage characteristics, optical modeling, and capacitance measurements, the combined diffusion length and depletion width in the PbS quantum dot layer is found to be approximately 170 nm.
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Affiliation(s)
- Liang-Yi Chang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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86
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Etgar L. Semiconductor Nanocrystals as Light Harvesters in Solar Cells. MATERIALS (BASEL, SWITZERLAND) 2013; 6:445-459. [PMID: 28809318 PMCID: PMC5452091 DOI: 10.3390/ma6020445] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 01/14/2013] [Accepted: 01/16/2013] [Indexed: 11/20/2022]
Abstract
Photovoltaic cells use semiconductors to convert sunlight into electrical current and are regarded as a key technology for a sustainable energy supply. Quantum dot-based solar cells have shown great potential as next generation, high performance, low-cost photovoltaics due to the outstanding optoelectronic properties of quantum dots and their multiple exciton generation (MEG) capability. This review focuses on QDs as light harvesters in solar cells, including different structures of QD-based solar cells, such as QD heterojunction solar cells, QD-Schottky solar cells, QD-sensitized solar cells and the recent development in organic-inorganic perovskite heterojunction solar cells. Mechanisms, procedures, advantages, disadvantages and the latest results obtained in the field are described. To summarize, a future perspective is offered.
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Affiliation(s)
- Lioz Etgar
- Institute of Chemistry, Casali Institute of Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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87
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Lee J, Mubeen S, Hernandez-Sosa G, Sun Y, Toma FM, Stucky GD, Moskovits M. High-efficiency panchromatic hybrid Schottky solar cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:256-260. [PMID: 23090941 DOI: 10.1002/adma.201202451] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Revised: 08/29/2012] [Indexed: 06/01/2023]
Abstract
Nanostructured Schottky inorganic-organic solar cells provide overall power conversion efficiencies exceeding 3%, with extremely large short-circuit photocurrents. The device EQE faithfully tracks the absorptance of the CdSe nanorods, and the IQE is approximately constant over the entire visible spectrum as opposed to a p-n junction hybrid solar cell fabricated with a highly absorbing organic polymer.
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Affiliation(s)
- Joun Lee
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA
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88
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Kershaw SV, Susha AS, Rogach AL. Narrow bandgap colloidal metal chalcogenide quantum dots: synthetic methods, heterostructures, assemblies, electronic and infrared optical properties. Chem Soc Rev 2013; 42:3033-87. [DOI: 10.1039/c2cs35331h] [Citation(s) in RCA: 325] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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89
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Zhang J, Su X, Shen M, Dai Z, Zhang L, He X, Cheng W, Cao M, Zou G. Enlarging photovoltaic effect: combination of classic photoelectric and ferroelectric photovoltaic effects. Sci Rep 2013; 3:2109. [PMID: 23811832 PMCID: PMC3696897 DOI: 10.1038/srep02109] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 06/14/2013] [Indexed: 11/09/2022] Open
Abstract
Converting light energy to electrical energy in photovoltaic devices relies on the photogenerated electrons and holes separated by the built-in potential in semiconductors. Photo-excited electrons in metal electrodes are usually not considered in this process. Here, we report an enhanced photovoltaic effect in the ferroelectric lanthanum-modified lead zirconate titanate (PLZT) by using low work function metals as the electrodes. We believe that electrons in the metal with low work function could be photo-emitted into PLZT and form the dominant photocurrent in our devices. Under AM1.5 (100 mW/cm²) illumination, the short-circuit current and open-circuit voltage of Mg/PLZT/ITO are about 150 and 2 times of those of Pt/PLZT/ITO, respectively. The photovoltaic response of PLZT capacitor was expanded from ultraviolet to visible spectra, and it may have important impact on design and fabrication of high performance photovoltaic devices based on ferroelectric materials.
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Affiliation(s)
- Jingjiao Zhang
- Jiangsu Key Laboratory of Thin Films, Photovoltaic Research Institute of Soochow University & Canadian Solar Inc., Department of Physics, Soochow University, 1 Shizi street, Suzhou, 215006, P. R. China
| | - Xiaodong Su
- Jiangsu Key Laboratory of Thin Films, Photovoltaic Research Institute of Soochow University & Canadian Solar Inc., Department of Physics, Soochow University, 1 Shizi street, Suzhou, 215006, P. R. China
| | - Mingrong Shen
- Jiangsu Key Laboratory of Thin Films, Photovoltaic Research Institute of Soochow University & Canadian Solar Inc., Department of Physics, Soochow University, 1 Shizi street, Suzhou, 215006, P. R. China
| | - Zhihua Dai
- Jiangsu Key Laboratory of Thin Films, Photovoltaic Research Institute of Soochow University & Canadian Solar Inc., Department of Physics, Soochow University, 1 Shizi street, Suzhou, 215006, P. R. China
| | - Lingjun Zhang
- Jiangsu Key Laboratory of Thin Films, Photovoltaic Research Institute of Soochow University & Canadian Solar Inc., Department of Physics, Soochow University, 1 Shizi street, Suzhou, 215006, P. R. China
| | - Xiyun He
- Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China
| | - Wenxiu Cheng
- Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China
| | - Mengyu Cao
- Jiangsu Key Laboratory of Thin Films, Photovoltaic Research Institute of Soochow University & Canadian Solar Inc., Department of Physics, Soochow University, 1 Shizi street, Suzhou, 215006, P. R. China
| | - Guifu Zou
- Jiangsu Key Laboratory of Thin Films, Photovoltaic Research Institute of Soochow University & Canadian Solar Inc., Department of Physics, Soochow University, 1 Shizi street, Suzhou, 215006, P. R. China
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90
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Wang Y, Li S, Shi H, Yu K. Facile synthesis of p-type Cu2O/n-type ZnO nano-heterojunctions with novel photoluminescence properties, enhanced field emission and photocatalytic activities. NANOSCALE 2012; 4:7817-7824. [PMID: 23147527 DOI: 10.1039/c2nr32797j] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Two kinds of Cu(2)O-ZnO nano-heteroarchitectures were fabricated through a hydrothermal method. By utilizing polyethyleneimine (PEI) as a binding agent, ZnO nanoparticles were uniformly self-assembled onto Cu(2)O micro structures. Photoluminescence (PL), field emission and photocatalytic activities of the composite samples were investigated and compared with those of the pure Cu(2)O samples. The results reveal that ZnO nanoparticles combined on Cu(2)O microstructures remarkably changed the PL signals, and significantly enhanced the field emission and photocatalytic activities. The novel PL properties, enhanced field emission and photocatalysis activities are attributed to the electron transition and the inhibition of photo-induced electron-hole pairs recombination, which stem from interfacial defect states and energy band differentials at the interface of Cu(2)O and ZnO. The surface nano-protrusions, large surface area and better dye adsorption induced by ZnO nanoparticles are responsible for the field emission and photocatalysis improvements as well.
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Affiliation(s)
- Yang Wang
- Key Laboratory of Polar Materials and Devices (Ministry of Education of China), Department of Electronic Engineering, East China Normal University, Shanghai 200241, PR China
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91
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Ning Z, Ren Y, Hoogland S, Voznyy O, Levina L, Stadler P, Lan X, Zhitomirsky D, Sargent EH. All-inorganic colloidal quantum dot photovoltaics employing solution-phase halide passivation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:6295-9. [PMID: 22968838 DOI: 10.1002/adma.201202942] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Indexed: 05/11/2023]
Abstract
A new solution-phase halide passivation strategy to improve the electronic properties of colloidal quantum dot films is reported. We prove experimentally that the approach leads to an order-of-magnitude increase in mobility and a notable reduction in trap state density. We build solar cells having the highest efficiency (6.6%) reported using all-inorganic colloidal quantum dots. The improved photocurrent results from increased efficiency of collection of infrared-generated photocarriers.
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Affiliation(s)
- Zhijun Ning
- Department of Electrical and Computer Engineering, University of Toronto, Ontario, Canada
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92
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Zhitomirsky D, Furukawa M, Tang J, Stadler P, Hoogland S, Voznyy O, Liu H, Sargent EH. N-type colloidal-quantum-dot solids for photovoltaics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:6181-5. [PMID: 22968808 DOI: 10.1002/adma.201202825] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 08/16/2012] [Indexed: 05/20/2023]
Abstract
N-type PbS colloidal-quantum-dot (CQD) films are fabricated using a controlled halide chemical treatment, applied in an inert processing ambient environment. The new materials exhibit a mobility of 0.1 cm(2) V(-1) s(-1) . The halogen ions serve both as a passivating agent and n-dope the films via substitution at surface chalcogen sites. The majority electron concentration across the range 10(16) to 10(18) cm(-3) is varied systematically.
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Affiliation(s)
- David Zhitomirsky
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
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93
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Deng J, Wang M, Song X, Shi Y, Zhang X. CdS and CdSe quantum dots subsectionally sensitized solar cells using a novel double-layer ZnO nanorod arrays. J Colloid Interface Sci 2012; 388:118-22. [DOI: 10.1016/j.jcis.2012.08.017] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/07/2012] [Accepted: 08/08/2012] [Indexed: 11/26/2022]
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94
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Lee JW, Im JH, Park NG. Quantum confinement effect of CdSe induced by nanoscale solvothermal reaction. NANOSCALE 2012; 4:6642-6648. [PMID: 22986805 DOI: 10.1039/c2nr31807e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report a novel method, nanoscale solvothermal reaction (NSR), to induce the quantum confinement effect of CdSe on nanostructured TiO(2) by solvothermal route. The time-dependent growth of CdSe is observed in solution at room temperature, which is found to be accomplished instantly by heat-treatment in the presence of solvent at 1 atm. However, no crystal growth occurs upon heat-treatment in the absence of solvent. The nanoscale solvothermal growth of CdSe quantum dot is realized on the nanocrystalline oxide surface, where Cd(NO(3))(2)·4H(2)O and Na(2)SeSO(3) solutions are sequentially spun on nanostructured TiO(2), followed by heat-treatment at temperatures ranging from 100 °C to 250 °C. Size of CdSe increases from 4.4 nm to 5.3 nm, 8.7 nm and 14.8 nm, which results in decrease in optical band gap from 2.19 eV to, 1.95 eV, 1.74 eV and 1.75 eV with increasing the NSR temperature from 100 °C to 150 °C, 200 °C and 250 °C, respectively, which is indicative of the quantum confinement effect. Thermodynamic studies reveal that increase in the size of CdSe is related to increase in enthalpy, for instance, from 3.77 J mg(-1) for 100 °C to 8.66 J mg(-1) for 200 °C. Quantum confinement effect is further confirmed from the CdSe-sensitized solar cell, where onset wavelength in external quantum efficiency spectra is progressively shifted from 600 nm to 800 nm as the NSR temperature increases, which leads to a significant improvement of power conversion efficiency by a factor of more than four. A high photocurrent density of 13.7 mA cm(-2) is obtained based on CdSe quantum dot grown by NSR at 200 °C.
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Affiliation(s)
- Jin-Wook Lee
- School of Chemical Engineering and Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Korea
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95
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Zhai G, Church CP, Breeze AJ, Zhang D, Alers GB, Carter SA. Quantum dot PbS(0.9)Se(0.1)/TiO2 heterojunction solar cells. NANOTECHNOLOGY 2012; 23:405401. [PMID: 22997175 DOI: 10.1088/0957-4484/23/40/405401] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report on photovoltaic cells based on ternary PbS(0.9)Se(0.1) quantum dots utilizing a heterojunction type device configuration. The best device shows an AM 1.5 power conversion efficiency of 4.25%. Furthermore, this ternary PbS(x)Se(1-x) quantum dot heterojunction device has a peak external quantum efficiency above 100% at 2.76 eV, approximately 2.7× the bandgap energy. The ternary quantum dots combine the higher short circuit currents of the binary PbSe system with the higher open circuit voltages of the binary PbS system.
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Affiliation(s)
- Guangmei Zhai
- Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
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96
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Etgar L, Gao P, Xue Z, Peng Q, Chandiran AK, Liu B, Nazeeruddin MK, Grätzel M. Mesoscopic CH3NH3PbI3/TiO2 Heterojunction Solar Cells. J Am Chem Soc 2012; 134:17396-9. [DOI: 10.1021/ja307789s] [Citation(s) in RCA: 1642] [Impact Index Per Article: 136.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Lioz Etgar
- Laboratoire de Photonique et
Interfaces, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne, Switzerland
- Institute of
Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904,
Israel
| | - Peng Gao
- Laboratoire de Photonique et
Interfaces, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne, Switzerland
| | - Zhaosheng Xue
- Department
of Chemical and Biomolecular
Engineering, National University of Singapore, Singapore
| | - Qin Peng
- Laboratoire de Photonique et
Interfaces, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne, Switzerland
| | - Aravind Kumar Chandiran
- Laboratoire de Photonique et
Interfaces, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne, Switzerland
| | - Bin Liu
- Department
of Chemical and Biomolecular
Engineering, National University of Singapore, Singapore
| | - Md. K. Nazeeruddin
- Laboratoire de Photonique et
Interfaces, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne, Switzerland
| | - Michael Grätzel
- Laboratoire de Photonique et
Interfaces, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne, Switzerland
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97
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Voznyy O, Zhitomirsky D, Stadler P, Ning Z, Hoogland S, Sargent EH. A charge-orbital balance picture of doping in colloidal quantum dot solids. ACS NANO 2012; 6:8448-55. [PMID: 22928602 DOI: 10.1021/nn303364d] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We present a framework--validated using both modeling and experiment--to predict doping in CQD films. In the ionic semiconductors widely deployed in CQD films, the framework reduces to a simple accounting of the contributions of the oxidation state of each constituent, including both inorganic species and organic ligands. We use density functional theory simulations to confirm that the type of doping can be reliably predicted based on the overall stoichiometry of the CQDs, largely independent of microscopic geometrical bonding configurations. Studies employing field-effect transistors constructed from CQDs that have undergone various chemical treatments, coupled with Rutherford backscattering and X-ray photoelectron spectroscopy to provide compositional analysis, allow us to test and confirm the proposed model in an experimental framework. We investigate both p- and n-type electronic doping spanning a wide range of carrier concentrations from 10(16) cm(-3) to over 10(18) cm(-3), and demonstrate reversible switching between p- and n-type doping by changing the CQD stoichiometry. We show that the summation of the contributions from all cations and anions within the film can be used to predict accurately the majority carrier type. The findings enable predictable control over majority carrier concentration via tuning of the overall stoichiometry.
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Affiliation(s)
- Oleksandr Voznyy
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
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98
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Tang J, Liu H, Zhitomirsky D, Hoogland S, Wang X, Furukawa M, Levina L, Sargent EH. Quantum junction solar cells. NANO LETTERS 2012; 12:4889-94. [PMID: 22881834 DOI: 10.1021/nl302436r] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Colloidal quantum dot solids combine convenient solution-processing with quantum size effect tuning, offering avenues to high-efficiency multijunction cells based on a single materials synthesis and processing platform. The highest-performing colloidal quantum dot rectifying devices reported to date have relied on a junction between a quantum-tuned absorber and a bulk material (e.g., TiO(2)); however, quantum tuning of the absorber then requires complete redesign of the bulk acceptor, compromising the benefits of facile quantum tuning. Here we report rectifying junctions constructed entirely using inherently band-aligned quantum-tuned materials. Realizing these quantum junction diodes relied upon the creation of an n-type quantum dot solid having a clean bandgap. We combine stable, chemically compatible, high-performance n-type and p-type materials to create the first quantum junction solar cells. We present a family of photovoltaic devices having widely tuned bandgaps of 0.6-1.6 eV that excel where conventional quantum-to-bulk devices fail to perform. Devices having optimal single-junction bandgaps exhibit certified AM1.5 solar power conversion efficiencies of 5.4%. Control over doping in quantum solids, and the successful integration of these materials to form stable quantum junctions, offers a powerful new degree of freedom to colloidal quantum dot optoelectronics.
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Affiliation(s)
- Jiang Tang
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074, China
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99
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de Kergommeaux A, Faure-Vincent J, Pron A, de Bettignies R, Malaman B, Reiss P. Surface Oxidation of Tin Chalcogenide Nanocrystals Revealed by 119Sn–Mössbauer Spectroscopy. J Am Chem Soc 2012; 134:11659-66. [DOI: 10.1021/ja3033313] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Antoine de Kergommeaux
- CEA Grenoble, INAC, UMR 5819
SPrAM (CEA/CNRS/UJF-Grenoble 1), Laboratoire d’Electronique Moléculaire, Organique et Hybride, 17 rue des
Martyrs, 38054 Grenoble cedex 9, France
- INES, CEA-DRT/LITEN/DTS/LMPV, Institut National de l’Energie Solaire, Le Bourget
du Lac, France
| | - Jérôme Faure-Vincent
- CEA Grenoble, INAC, UMR 5819
SPrAM (CEA/CNRS/UJF-Grenoble 1), Laboratoire d’Electronique Moléculaire, Organique et Hybride, 17 rue des
Martyrs, 38054 Grenoble cedex 9, France
| | - Adam Pron
- CEA Grenoble, INAC, UMR 5819
SPrAM (CEA/CNRS/UJF-Grenoble 1), Laboratoire d’Electronique Moléculaire, Organique et Hybride, 17 rue des
Martyrs, 38054 Grenoble cedex 9, France
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3 00664
Warszawa, Poland
| | - Rémi de Bettignies
- INES, CEA-DRT/LITEN/DTS/LMPV, Institut National de l’Energie Solaire, Le Bourget
du Lac, France
| | - Bernard Malaman
- Institut Jean
Lamour, Université de Lorraine,
UMR 7198, B.P. 70239,
54506 Vandoeuvre-les-Nancy Cedex, France
| | - Peter Reiss
- CEA Grenoble, INAC, UMR 5819
SPrAM (CEA/CNRS/UJF-Grenoble 1), Laboratoire d’Electronique Moléculaire, Organique et Hybride, 17 rue des
Martyrs, 38054 Grenoble cedex 9, France
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100
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Anthony RJ, Cheng KY, Holman ZC, Holmes RJ, Kortshagen UR. An all-gas-phase approach for the fabrication of silicon nanocrystal light-emitting devices. NANO LETTERS 2012; 12:2822-2825. [PMID: 22519583 DOI: 10.1021/nl300164z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present an all-gas-phase approach for the fabrication of nanocrystal-based light-emitting devices. In a single reactor, silicon nanocrystals are synthesized, surface-functionalized, and deposited onto substrates precoated with a transparent electrode. Devices are completed by evaporation of a top metal electrode. The devices exhibit electroluminescence centered at a wavelength of λ = 836 nm with a peak external quantum efficiency exceeding 0.02%. This all-gas-phase approach permits controlled deposition of dense, functional nanocrystal films suitable for application in electronic devices.
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Affiliation(s)
- Rebecca J Anthony
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States.
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