1
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Pang C, Deng YH, Kheradmand E, Poonkottil N, Petit R, Elsinger L, Detavernier C, Geiregat P, Hens Z, Van Thourhout D. Integrated PbS Colloidal Quantum Dot Photodiodes on Silicon Nitride Waveguides. ACS PHOTONICS 2023; 10:4215-4224. [PMID: 38145169 PMCID: PMC10741659 DOI: 10.1021/acsphotonics.3c00945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Indexed: 12/26/2023]
Abstract
Colloidal quantum dots (QDs) have become a versatile optoelectronic material for emitting and detecting light that can overcome the limitations of a range of electronic and photonic technology platforms. Photonic integrated circuits (PICs), for example, face the persistent challenge of combining active materials with passive circuitry ideally suited for guiding light. Here, we demonstrate the integration of photodiodes (PDs) based on PbS QDs on silicon nitride waveguides (WG). Analyzing planar QDPDs first, we argue that the main limitation WG-coupled QDPDs face is detector saturation induced by the high optical power density of the guided light. Using the cladding thickness and waveguide width as design parameters, we mitigate this issue, and we demonstrate WG-QDPDs with an external quantum efficiency of 67.5% at 1275 nm that exhibit a linear photoresponse for input powers up to 400 nW. In the next step, we demonstrate a compact infrared spectrometer by integrating these WG-QDPDs on the output channels of an arrayed waveguide grating demultiplexer. This work provides a path toward a low-cost PD solution for PICs, which are attractive for large-scale production.
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Affiliation(s)
- Chao Pang
- Photonics
Research Group, Ghent University - imec, 9052 Ghent, Belgium
- NB
Photonics, Ghent University, 9052 Ghent, Belgium
| | - Yu-Hao Deng
- NB
Photonics, Ghent University, 9052 Ghent, Belgium
- Physics
and Chemistry of Nanostructures Group, Ghent
University, 9000 Ghent, Belgium
| | - Ezat Kheradmand
- NB
Photonics, Ghent University, 9052 Ghent, Belgium
- Physics
and Chemistry of Nanostructures Group, Ghent
University, 9000 Ghent, Belgium
| | - Nithin Poonkottil
- NB
Photonics, Ghent University, 9052 Ghent, Belgium
- Conformal
Coating of Nanomaterials Group, Ghent University, 9000 Ghent, Belgium
| | - Robin Petit
- NB
Photonics, Ghent University, 9052 Ghent, Belgium
- Conformal
Coating of Nanomaterials Group, Ghent University, 9000 Ghent, Belgium
| | - Lukas Elsinger
- Photonics
Research Group, Ghent University - imec, 9052 Ghent, Belgium
- NB
Photonics, Ghent University, 9052 Ghent, Belgium
| | - Christophe Detavernier
- NB
Photonics, Ghent University, 9052 Ghent, Belgium
- Conformal
Coating of Nanomaterials Group, Ghent University, 9000 Ghent, Belgium
| | - Pieter Geiregat
- NB
Photonics, Ghent University, 9052 Ghent, Belgium
- Physics
and Chemistry of Nanostructures Group, Ghent
University, 9000 Ghent, Belgium
| | - Zeger Hens
- NB
Photonics, Ghent University, 9052 Ghent, Belgium
- Physics
and Chemistry of Nanostructures Group, Ghent
University, 9000 Ghent, Belgium
| | - Dries Van Thourhout
- Photonics
Research Group, Ghent University - imec, 9052 Ghent, Belgium
- NB
Photonics, Ghent University, 9052 Ghent, Belgium
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2
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Mahmood AU, Rizvi MH, Tracy JB, Yingling YG. Solvent Effects in Ligand Stripping Behavior of Colloidal Nanoparticles. ACS NANO 2023. [PMID: 37311219 DOI: 10.1021/acsnano.3c01313] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Inorganic colloidal nanoparticle (NP) properties can be tuned by stripping stabilizing ligands using a poor solvent. However, the mechanism behind ligand stripping is poorly understood, in part because in situ measurements of ligand stripping are challenging at the nanoscale. Here, we investigate ethanol solvent-mediated oleylamine ligand stripping from magnetite (Fe3O4) NPs in different compositions of ethanol/hexane mixtures using atomistic molecular dynamics (MD) simulations and thermogravimetric analysis (TGA). Our study elucidates a complex interplay of ethanol interactions with system components and indicates the existence of a threshold concentration of ∼34 vol % ethanol, above which ligand stripping saturates. Moreover, hydrogen bonding between ethanol and stripped ligands inhibits subsequent readsorption of the ligands on the NP surface. A proposed modification of the Langmuir isotherm explains the role of the enthalpy of mixing of the ligands and solvents on the ligand stripping mechanism. A good agreement between the MD predictions and TGA measurements of ligand stripping from Fe3O4 NPs validates the simulation observations. Our findings demonstrate that the ligand coverage of NPs can be controlled by using a poor solvent below the threshold concentration and highlight the importance of ligand-solvent interactions that modulate the properties of colloidal NPs. The study also provides an approach for a detailed in silico study of ligand stripping and exchange from colloidal NPs that are crucial for applications of NPs spanning self-assembly, optoelectronics, nanomedicine, and catalysis.
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Affiliation(s)
- Akhlak U Mahmood
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Mehedi H Rizvi
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Joseph B Tracy
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Yaroslava G Yingling
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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3
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Wei X, Zhang P, Xu T, Zhou H, Bai Y, Chen Q. Chemical approaches for electronic doping in photovoltaic materials beyond crystalline silicon. Chem Soc Rev 2022; 51:10016-10063. [PMID: 36398768 DOI: 10.1039/d2cs00110a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Electronic doping is applied to tailor the electrical and optoelectronic properties of semiconductors, which have been widely adopted in information and clean energy technologies, like integrated circuit fabrication and PVs. Though this concept has prevailed in conventional PVs, it has achieved limited success in the new-generation PV materials, particularly in halide perovskites, owing to their soft lattice nature and self-compensation by intrinsic defects. In this review, we summarize the evolution of the theoretical understanding and strategies of electronic doping from Si-based photovoltaics to thin-film technologies, e.g., GaAs, CdTe and Cu(In,Ga)Se2, and also cover the emerging PVs including halide perovskites and organic solar cells. We focus on the chemical approaches to electronic doping, emphasizing various chemical interactions/bonding throughout materials synthesis/modification to device fabrication/operation. Furthermore, we propose new classifications and models of electronic doping based on the physical and chemical properties of dopants, in the context of solid-state chemistry, which inspires further development of optoelectronics based on perovskites and other hybrid materials. Finally, we outline the effects of electronic doping in semiconducting materials and highlight the challenges that need to be overcome for reliable and controllable doping.
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Affiliation(s)
- Xueyuan Wei
- Experimental Centre for Advanced Materials, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China.
| | - Pengxiang Zhang
- Experimental Centre for Advanced Materials, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China.
| | - Tailai Xu
- Experimental Centre for Advanced Materials, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China.
| | - Huanping Zhou
- School of Materials Science and Engineering, Peking University, Beijing, 100871, P. R. China
| | - Yang Bai
- Experimental Centre for Advanced Materials, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China.
| | - Qi Chen
- Experimental Centre for Advanced Materials, School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China.
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4
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Liu X, Fu T, Liu J, Wang Y, Jia Y, Wang C, Li X, Zhang X, Liu Y. Solution Annealing Induces Surface Chemical Reconstruction for High-Efficiency PbS Quantum Dot Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2022; 14:14274-14283. [PMID: 35289178 DOI: 10.1021/acsami.2c01196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Colloidal quantum dots (CQDs) have a large specific surface area and a complex surface structure. Their properties in diverse optoelectronic applications are largely determined by their surface chemistry. Therefore, it is essential to investigate the surface chemistry of CQDs for improving device performance. Herein, we realized an efficient surface chemistry optimization of lead sulfide (PbS) CQDs for photovoltaics by annealing the CQD solution with concentrated lead halide ligands after the conventional solution-phase ligand exchange. During the annealing process, the colloidal solution was used to transfer heat and create a secondary reaction environment, promoting the desorption of electrically insulating oleate ligands as well as the trap-related surface groups (Pb-hydroxyl and oxidized Pb species). This was accompanied by the binding of more conductive lead halide ligands on the CQD surface, eventually achieving a more complete ligand exchange. Furthermore, this strategy also minimized CQD polydispersity and decreased aggregation caused by conventional solution-phase ligand exchange, thereby contributing to yielding CQD films with twofold enhanced carrier mobility and twofold reduced trap-state density compared with those of the control. Based on these merits, the fabricated PbS CQD solar cells showed high efficiency of 11% under ambient conditions. Our strategy opens a novel and effective avenue to obtain high-efficiency CQD solar cells with diverse band gaps, providing meaningful guidance for controlling ligand reactivity and realizing subtly purified CQDs.
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Affiliation(s)
- Xinlu Liu
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory of UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, Jilin, P. R. China
| | - Ting Fu
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory of UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, Jilin, P. R. China
| | - Jianping Liu
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory of UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, Jilin, P. R. China
| | - Yinglin Wang
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory of UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, Jilin, P. R. China
| | - Yuwen Jia
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory of UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, Jilin, P. R. China
| | - Chao Wang
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory of UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, Jilin, P. R. China
| | - Xiaofei Li
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory of UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, Jilin, P. R. China
| | - Xintong Zhang
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory of UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, Jilin, P. R. China
| | - Yichun Liu
- Center for Advanced Optoelectronic Functional Materials Research, and Key Laboratory of UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, Jilin, P. R. China
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5
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Yuan M, Wang X, Chen X, He J, Li K, Song B, Hu H, Gao L, Lan X, Chen C, Tang J. Phase-Transfer Exchange Lead Chalcogenide Colloidal Quantum Dots: Ink Preparation, Film Assembly, and Solar Cell Construction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2102340. [PMID: 34561947 DOI: 10.1002/smll.202102340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 07/23/2021] [Indexed: 06/13/2023]
Abstract
Solution-processed colloidal quantum dots (CQDs) are promising candidates for the third-generation photovoltaics due to their low cost and spectral tunability. The development of CQD solar cells mainly relies on high-quality CQD ink, smooth and dense film, and charge-extraction-favored device architectures. In particular, advances in the processing of CQDs are essential for high-quality QD solids. The phase transfer exchange (PTE), in contrast with traditional solid-state ligand exchange, has demonstrated to be the most promising approach for high-quality QD solids in terms of charge transport and defect passivation. As a result, the efficiencies of Pb chalcogenide CQD solar cells have been rapidly improved to 14.0%. In this review, the development of the PTE method is briefly reviewed for lead chalcogenide CQD ink preparation, film assembly, and device construction. Particularly, the key roles of lead halides and additional additives are emphasized for defect passivation and charge transport improvement. In the end, several potential directions for future research are proposed.
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Affiliation(s)
- Mohan Yuan
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, P. R. China
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Xia Wang
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, P. R. China
| | - Xiao Chen
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, P. R. China
| | - Jungang He
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan, 430205, P. R. China
| | - Kanghua Li
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Boxiang Song
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Huicheng Hu
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Liang Gao
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Xinzheng Lan
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Chao Chen
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
| | - Jiang Tang
- Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, P. R. China
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6
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Clark PCJ, Lewis NK, Ke JCR, Ahumada-Lazo R, Chen Q, Neo DCJ, Gaulding EA, Pach GF, Pis I, Silly MG, Flavell WR. Surface band bending and carrier dynamics in colloidal quantum dot solids. NANOSCALE 2021; 13:17793-17806. [PMID: 34668501 DOI: 10.1039/d1nr05436h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Band bending in colloidal quantum dot (CQD) solids has become important in driving charge carriers through devices. This is typically a result of band alignments at junctions in the device. Whether band bending is intrinsic to CQD solids, i.e. is band bending present at the surface-vacuum interface, has previously been unanswered. Here we use photoemission surface photovoltage measurements to show that depletion regions are present at the surface of n and p-type CQD solids with various ligand treatments (EDT, MPA, PbI2, MAI/PbI2). Using laser-pump photoemission-probe time-resolved measurements, we show that the timescale of carrier dynamics in the surface of CQD solids can vary over at least 6 orders of magnitude, with the fastest dynamics on the order of microseconds in PbS-MAI/PbI2 solids and on the order of seconds for PbS-MPA and PbS-PbI2. By investigating the surface chemistry of the solids, we find a correlation between the carrier dynamics timescales and the presence of oxygen contaminants, which we suggest are responsible for the slower dynamics due to deep trap formation.
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Affiliation(s)
- Pip C J Clark
- Department of Physics and Astronomy and the Photon Science Institute, The University of Manchester, Manchester M13 9PL, UK.
| | - Nathan K Lewis
- Department of Physics and Astronomy and the Photon Science Institute, The University of Manchester, Manchester M13 9PL, UK.
| | - Jack Chun-Ren Ke
- Department of Physics and Astronomy and the Photon Science Institute, The University of Manchester, Manchester M13 9PL, UK.
| | - Ruben Ahumada-Lazo
- Department of Physics and Astronomy and the Photon Science Institute, The University of Manchester, Manchester M13 9PL, UK.
| | - Qian Chen
- Department of Materials, The University of Manchester, Manchester M13 9PL, UK
| | - Darren C J Neo
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, USA
| | | | - Gregory F Pach
- National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Igor Pis
- Laboratorio TASC, IOM CNR, S.S. 14 km 163.5, 34149 Basovizza, Trieste, Italy
- Elettra-Sincrotrone Trieste S.C.p.A., S. S. 14 Km 163.5, 34149 Basovizza, Trieste, Italy
| | - Mathieu G Silly
- Synchrotron SOLEIL, BP 48, Saint-Aubin, F91192 Gif sur Yvette CEDEX, France
| | - Wendy R Flavell
- Department of Physics and Astronomy and the Photon Science Institute, The University of Manchester, Manchester M13 9PL, UK.
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7
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Kim HI, Baek SW, Choi MJ, Chen B, Ouellette O, Choi K, Scheffel B, Choi H, Biondi M, Hoogland S, García de Arquer FP, Park T, Sargent EH. Monolithic Organic/Colloidal Quantum Dot Hybrid Tandem Solar Cells via Buffer Engineering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2004657. [PMID: 32939875 DOI: 10.1002/adma.202004657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/07/2020] [Indexed: 06/11/2023]
Abstract
Monolithically integrated hybrid tandem solar cells (TSCs) that combine solution-processed colloidal quantum dot (CQD) and organic molecules are a promising device architecture, able to complement the absorption across the visible to the infrared. However, the performance of organic/CQD hybrid TSCs has not yet surpassed that of single-junction CQD solar cells. Here, a strategic optical structure is devised to overcome the prior performance limit of hybrid TSCs by employing a multibuffer layer and a dual near-infrared (NIR) absorber. In particular, a multibuffer layer is introduced to solve the problem of the CQD solvent penetrating the underlying organic layer. In addition, the matching current of monolithic TSCs is significantly improved to 15.2 mA cm-2 by using a dual NIR organic absorber that complements the absorption of CQD. The hybrid TSCs reach a power conversion efficiency (PCE) of 13.7%, higher than that of the corresponding individual single-junction cells, representing the highest efficiency reported to date for CQD-based hybrid TSCs.
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Affiliation(s)
- Hong Il Kim
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, 37673, South Korea
| | - Se-Woong Baek
- Department of Chemical and Biological Engineering, Korea University, 145 Anam-Ro, Seongbuk-Gu, Seoul, 02841, South Korea
| | - Min-Jae Choi
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Bin Chen
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Olivier Ouellette
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Kyoungwon Choi
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, 37673, South Korea
| | - Benjamin Scheffel
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Hyuntae Choi
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, 37673, South Korea
| | - Margherita Biondi
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Sjoerd Hoogland
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - F Pelayo García de Arquer
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Taiho Park
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk, 37673, South Korea
| | - Edward H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
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8
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Biondi M, Choi MJ, Ouellette O, Baek SW, Todorović P, Sun B, Lee S, Wei M, Li P, Kirmani AR, Sagar LK, Richter LJ, Hoogland S, Lu ZH, García de Arquer FP, Sargent EH. A Chemically Orthogonal Hole Transport Layer for Efficient Colloidal Quantum Dot Solar Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1906199. [PMID: 32196136 DOI: 10.1002/adma.201906199] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 01/25/2020] [Indexed: 06/10/2023]
Abstract
Colloidal quantum dots (CQDs) are of interest in light of their solution-processing and bandgap tuning. Advances in the performance of CQD optoelectronic devices require fine control over the properties of each layer in the device materials stack. This is particularly challenging in the present best CQD solar cells, since these employ a p-type hole-transport layer (HTL) implemented using 1,2-ethanedithiol (EDT) ligand exchange on top of the CQD active layer. It is established that the high reactivity of EDT causes a severe chemical modification to the active layer that deteriorates charge extraction. By combining elemental mapping with the spatial charge collection efficiency in CQD solar cells, the key materials interface dominating the subpar performance of prior CQD PV devices is demonstrated. This motivates to develop a chemically orthogonal HTL that consists of malonic-acid-crosslinked CQDs. The new crosslinking strategy preserves the surface chemistry of the active layer beneath, and at the same time provides the needed efficient charge extraction. The new HTL enables a 1.4× increase in charge carrier diffusion length in the active layer; and as a result leads to an improvement in power conversion efficiency to 13.0% compared to EDT standard cells (12.2%).
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Affiliation(s)
- Margherita Biondi
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Min-Jae Choi
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Olivier Ouellette
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Se-Woong Baek
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Petar Todorović
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Bin Sun
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Seungjin Lee
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Mingyang Wei
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Peicheng Li
- Department of Material Science and Engineering, University of Toronto, 184 College St, Toronto, Ontario, M5S 3E4, Canada
| | - Ahmad R Kirmani
- Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA
| | - Laxmi K Sagar
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Lee J Richter
- Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD, 20899, USA
| | - Sjoerd Hoogland
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Zheng-Hong Lu
- Department of Material Science and Engineering, University of Toronto, 184 College St, Toronto, Ontario, M5S 3E4, Canada
| | - F Pelayo García de Arquer
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
| | - Edward H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4, Canada
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9
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Lin WMM, Yazdani N, Yarema O, Volk S, Yarema M, Kirchartz T, Wood V. Simulating nanocrystal-based solar cells: A lead sulfide case study. J Chem Phys 2019; 151:241104. [DOI: 10.1063/1.5129159] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Weyde M. M. Lin
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Nuri Yazdani
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Olesya Yarema
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Sebastian Volk
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Maksym Yarema
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Thomas Kirchartz
- IEK-5 Photovoltaik, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Faculty of Engineering and CENIDE, University of Duisburg-Essen, Carl-Benz-Str. 199, 47057 Duisburg, Germany
| | - Vanessa Wood
- Materials and Device Engineering Group, Department of Information Technology and Electrical Engineering, ETH Zurich, 8092 Zurich, Switzerland
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10
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Zhao H, Li Y, Diao L, Sun C, Shi Y. Reevaluating the effects of reorganization energy on electron transfer rate for quantum dot-molecular acceptor complexes in different solvents. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 218:237-242. [PMID: 31003048 DOI: 10.1016/j.saa.2019.04.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/28/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
The electron transfer (ET) rate in quantum dot (QD)-molecular acceptor systems is dependent upon system reorganization energy (RE, λ), which comprises contributions from solvent (λ0) and reactants (λi). However, to date, the effect of λi on ET rate has been largely ignored. Herein, the ET from CdSe/ZnS QDs to 1-chloroanthraquinone (1-CAQ) in different solvents was investigated using ultrafast transient absorption spectroscopy as a means to evaluate the effect of λi on ET rate. The results revealed that ET rate is strongly solvent dependent. Amazingly, the ET rate in carbon disulfide is 300-times higher than that in n-dodecane. Theoretical calculations indicated that the λi contribution from 1-CAQ alone accounts for a large proportion of system RE and varies greatly in different solvents. Furthermore, the ET rate increases first and, then, decreases with the λ value in different solvents. This trend was interpreted consistently in terms of Marcus theory by adding λi to λ for different solvents. Thus, our present work demonstrates that the RE of the acceptor molecule has a non-negligible effect on ET rate, providing new insight into the mechanisms of ET process and for the development of QD-based devices.
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Affiliation(s)
- Huifang Zhao
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - You Li
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Lihe Diao
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Chaofan Sun
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Ying Shi
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China.
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11
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Kirmani AR, Sheikh AD, Niazi MR, Haque MA, Liu M, de Arquer FPG, Xu J, Sun B, Voznyy O, Gasparini N, Baran D, Wu T, Sargent EH, Amassian A. Overcoming the Ambient Manufacturability-Scalability-Performance Bottleneck in Colloidal Quantum Dot Photovoltaics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1801661. [PMID: 29978514 DOI: 10.1002/adma.201801661] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 04/21/2018] [Indexed: 05/22/2023]
Abstract
Colloidal quantum dot (CQD) solar cells have risen rapidly in performance; however, their low-cost fabrication under realistic ambient conditions remains elusive. This study uncovers that humid environments curtail the power conversion efficiency (PCE) of solar cells by preventing the needed oxygen doping of the hole transporter during ambient fabrication. A simple oxygen-doping step enabling ambient manufacturing irrespective of seasonal humidity variations is devised. Solar cells with PCE > 10% are printed under high humidity at industrially viable speeds. The devices use a tiny fraction of the ink typically needed and are air stable over a year. The humidity-resilient fabrication of efficient CQD solar cells breaks a long-standing compromise, which should accelerate commercialization.
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Affiliation(s)
- Ahmad R Kirmani
- Physical Sciences and Engineering Division, KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Arif D Sheikh
- Physical Sciences and Engineering Division, KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Muhammad R Niazi
- Physical Sciences and Engineering Division, KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Md Azimul Haque
- Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Mengxia Liu
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, M5S 3G4, Canada
| | - F Pelayo García de Arquer
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, M5S 3G4, Canada
| | - Jixian Xu
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, M5S 3G4, Canada
| | - Bin Sun
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, M5S 3G4, Canada
| | - Oleksandr Voznyy
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, M5S 3G4, Canada
| | - Nicola Gasparini
- Physical Sciences and Engineering Division, KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Derya Baran
- Physical Sciences and Engineering Division, KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Tom Wu
- Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Edward H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, M5S 3G4, Canada
| | - Aram Amassian
- Physical Sciences and Engineering Division, KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
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12
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Clark PCJ, Neo DCJ, Ahumada-Lazo R, Williamson AI, Pis I, Nappini S, Watt AAR, Flavell WR. Influence of Multistep Surface Passivation on the Performance of PbS Colloidal Quantum Dot Solar Cells. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:8887-8897. [PMID: 29975548 DOI: 10.1021/acs.langmuir.8b01453] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The performance of devices containing colloidal quantum dot (CQD) films is strongly dependent on the surface chemistry of the CQDs they contain. Multistep surface treatments, which combine two or more strategies, are important for creating films with high carrier mobility that are well passivated against trap states and oxidation. Here, we examine the effect of a number of these surface treatments on PbS CQD films, including cation exchange to form PbS/CdS core/shell CQDs, and solid-state ligand-exchange treatments with Cl, Br, I, and 1,2-ethanedithiol (EDT) ligands. Using laboratory-based and synchrotron-radiation-excited X-ray photoelectron spectroscopy (XPS), we examine the compositions of the surface layer before and after treatment, and correlate this with the performance data and stability in air. We find that halide ion treatments may etch the CQD surfaces, with detrimental effects on the air stability and solar cell device performance caused by a reduction in the proportion of passivated surface sites. We show that films made up of PbS/CdS CQDs are particularly prone to this, suggesting Cd is more easily etched from the surface than Pb. However, by choosing a less aggressive ligand treatment, a good coverage of passivators on the surface can be achieved. We show that halide anions bind preferentially to surface Pb (rather than Cd). By isolating the part of XPS signal originating from the topmost surface layer of the CQD, we show that air stability is correlated with the total number of passivating agents (halide + EDT + Cd) at the surface.
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Affiliation(s)
- Pip C J Clark
- School of Physics and Astronomy and the Photon Science Institute , The University of Manchester , Manchester M13 9PL , United Kingdom
| | - Darren C J Neo
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Ruben Ahumada-Lazo
- School of Physics and Astronomy and the Photon Science Institute , The University of Manchester , Manchester M13 9PL , United Kingdom
| | - Andrew I Williamson
- School of Physics and Astronomy and the Photon Science Institute , The University of Manchester , Manchester M13 9PL , United Kingdom
| | - Igor Pis
- Elettra-Sincrotrone Trieste S.C.p.A. , S. S. 14 km 163.5 , Basovizza 34149 , Trieste , Italy
| | - Silvia Nappini
- Laboratorio TASC, IOM CNR , S. S. 14 km 163.5 , Basovizza 34149 , Trieste , Italy
| | - Andrew A R Watt
- Department of Materials , University of Oxford , 16 Parks Road , Oxford OX1 3PH , United Kingdom
| | - Wendy R Flavell
- School of Physics and Astronomy and the Photon Science Institute , The University of Manchester , Manchester M13 9PL , United Kingdom
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13
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Zhang Y, Wu G, Ding C, Liu F, Yao Y, Zhou Y, Wu C, Nakazawa N, Huang Q, Toyoda T, Wang R, Hayase S, Zou Z, Shen Q. Lead Selenide Colloidal Quantum Dot Solar Cells Achieving High Open-Circuit Voltage with One-Step Deposition Strategy. J Phys Chem Lett 2018; 9:3598-3603. [PMID: 29905077 DOI: 10.1021/acs.jpclett.8b01514] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Lead selenide (PbSe) colloidal quantum dots (CQDs) are considered to be a strong candidate for high-efficiency colloidal quantum dot solar cells (CQDSCs) due to its efficient multiple exciton generation. However, currently, even the best PbSe CQDSCs can only display open-circuit voltage ( Voc) about 0.530 V. Here, we introduce a solution-phase ligand exchange method to prepare PbI2-capped PbSe (PbSe-PbI2) CQD inks, and for the first time, the absorber layer of PbSe CQDSCs was deposited in one step by using this PbSe-PbI2 CQD inks. One-step-deposited PbSe CQDs absorber layer exhibits fast charge transfer rate, reduced energy funneling, and low trap assisted recombination. The champion large-area (active area is 0.35 cm2) PbSe CQDSCs fabricated with one-step PbSe CQDs achieve a power conversion efficiency (PCE) of 6.0% and a Voc of 0.616 V, which is the highest Voc among PbSe CQDSCs reported to date.
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Affiliation(s)
- Yaohong Zhang
- Faculty of Informatics and Engineering , The University of Electro-Communications , Tokyo 182-8585 , Japan
| | - Guohua Wu
- School of Materials Science and Engineering , Shaanxi Normal University , Xi'an 710119 , China
| | - Chao Ding
- Faculty of Informatics and Engineering , The University of Electro-Communications , Tokyo 182-8585 , Japan
| | - Feng Liu
- Faculty of Informatics and Engineering , The University of Electro-Communications , Tokyo 182-8585 , Japan
| | - Yingfang Yao
- Ecomaterials and Renewable Energy Research Center, Jiangsu Key Laboratory for Nano Technology, National Laboratory of Solid State Microstructures , Nanjing University , Nanjing 210093 , China
| | - Yong Zhou
- Ecomaterials and Renewable Energy Research Center, Jiangsu Key Laboratory for Nano Technology, National Laboratory of Solid State Microstructures , Nanjing University , Nanjing 210093 , China
| | - Congping Wu
- Kunshan Sunlaite New Energy Technology Co. Ltd ., Suzhou 215347 , China
| | - Naoki Nakazawa
- Faculty of Informatics and Engineering , The University of Electro-Communications , Tokyo 182-8585 , Japan
| | - Qingxun Huang
- Faculty of Informatics and Engineering , The University of Electro-Communications , Tokyo 182-8585 , Japan
| | - Taro Toyoda
- Faculty of Informatics and Engineering , The University of Electro-Communications , Tokyo 182-8585 , Japan
| | - Ruixiang Wang
- Beijing Engineering Research Centre of Sustainable Energy and Buildings , Beijing University of Civil Engineering and Architecture , Beijing 102616 , China
| | - Shuzi Hayase
- Faculty of Life Science and Systems Engineering , Kyushu Institute of Technology , Fukuoka 808-0196 , Japan
| | - Zhigang Zou
- Ecomaterials and Renewable Energy Research Center, Jiangsu Key Laboratory for Nano Technology, National Laboratory of Solid State Microstructures , Nanjing University , Nanjing 210093 , China
- Kunshan Sunlaite New Energy Technology Co. Ltd ., Suzhou 215347 , China
| | - Qing Shen
- Faculty of Informatics and Engineering , The University of Electro-Communications , Tokyo 182-8585 , Japan
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14
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Lu K, Wang Y, Liu Z, Han L, Shi G, Fang H, Chen J, Ye X, Chen S, Yang F, Shulga AG, Wu T, Gu M, Zhou S, Fan J, Loi MA, Ma W. High-Efficiency PbS Quantum-Dot Solar Cells with Greatly Simplified Fabrication Processing via "Solvent-Curing". ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1707572. [PMID: 29718542 DOI: 10.1002/adma.201707572] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 03/02/2018] [Indexed: 05/09/2023]
Abstract
PbS quantum-dot (QD) solar cells are promising candidates for low-cost solution-processed photovoltaics. However, the device fabrication usually requires ten more times film deposition and rinsing steps, which is not ideal for scalable manufacturing. Here, a greatly simplified deposition processing is demonstrated by replacing methanol with acetonitrile (ACN) as the rinsing solvent. It is discovered that ACN can effectively "cure" the film cracks generated from the volume loss during the solid-state ligand-exchange process, which enables the deposition of thick and dense films with much fewer deposition steps. Meanwhile, due to the aprotic nature of ACN, fewer trap states can be introduced during the rinsing process. As a result, with only three deposition steps for the active layer, a CPVT-certified 11.21% power conversion efficiency is obtained, which is the highest efficiency ever reported for PbS QD solar cells employing a solid-state ligand-exchange process. More importantly, the simple film-deposition processing provides an opportunity for the future application of QDs in low-cost printing of optoelectronic devices.
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Affiliation(s)
- Kunyuan Lu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, P. R. China
| | - Yongjie Wang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, P. R. China
| | - Zeke Liu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, P. R. China
| | - Lu Han
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, P. R. China
| | - Guozheng Shi
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, P. R. China
| | - Honghua Fang
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, The Netherlands
| | - Jun Chen
- Department of Chemistry, Indiana University, Bloomington, 800 E. Kirkwood Ave., Bloomington, IN, 47405, USA
| | - Xingchen Ye
- Department of Chemistry, Indiana University, Bloomington, 800 E. Kirkwood Ave., Bloomington, IN, 47405, USA
| | - Si Chen
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, P. R. China
| | - Fan Yang
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, P. R. China
| | - Artem G Shulga
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, The Netherlands
| | - Tian Wu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, P. R. China
| | - Mengfan Gu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, P. R. China
| | - Sijie Zhou
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, P. R. China
| | - Jian Fan
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, P. R. China
| | - Maria Antonietta Loi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, The Netherlands
| | - Wanli Ma
- Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, P. R. China
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15
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Yazdani N, Nguyen-Thanh T, Yarema M, Lin WMM, Gao R, Yarema O, Bosak A, Wood V. Measuring the Vibrational Density of States of Nanocrystal-Based Thin Films with Inelastic X-ray Scattering. J Phys Chem Lett 2018; 9:1561-1567. [PMID: 29518338 DOI: 10.1021/acs.jpclett.8b00409] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Knowledge of the vibrational structure of a semiconductor is essential for explaining its optical and electronic properties and enabling optimized materials selection for optoelectronic devices. However, measurement of the vibrational density of states of nanomaterials is challenging. Here, using the example of colloidal nanocrystals (quantum dots), we show that the vibrational density of states of nanomaterials can be accurately and efficiently measured with inelastic X-ray scattering (IXS). Using IXS, we report the first experimental measurements of the vibrational density of states for lead sulfide nanocrystals with different halide-ion terminations and for CsPbBr3 perovskite nanocrystals. IXS findings are supported with ab initio molecular dynamics simulations, which provide insight into the origin of the measured vibrational structure and the effect of nanocrystal surface. Our findings highlight the advantages of IXS compared to other methods for measuring the vibrational density of states of nanocrystals such as inelastic neutron scattering and Raman scattering.
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Affiliation(s)
- Nuri Yazdani
- Department of Information Technology and Electrical Engineering , ETH Zurich , Zurich , 8092 Switzerland
| | - Tra Nguyen-Thanh
- European Synchrotron Radiation Facility , 71, Avenue des Martyrs , F-38000 Grenoble , France
| | - Maksym Yarema
- Department of Information Technology and Electrical Engineering , ETH Zurich , Zurich , 8092 Switzerland
| | - Weyde M M Lin
- Department of Information Technology and Electrical Engineering , ETH Zurich , Zurich , 8092 Switzerland
| | - Ramon Gao
- Department of Information Technology and Electrical Engineering , ETH Zurich , Zurich , 8092 Switzerland
| | - Olesya Yarema
- Department of Information Technology and Electrical Engineering , ETH Zurich , Zurich , 8092 Switzerland
| | - Alexey Bosak
- European Synchrotron Radiation Facility , 71, Avenue des Martyrs , F-38000 Grenoble , France
| | - Vanessa Wood
- Department of Information Technology and Electrical Engineering , ETH Zurich , Zurich , 8092 Switzerland
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16
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Wu H, Li X, Tung C, Wu L. Recent Advances in Sensitized Photocathodes: From Molecular Dyes to Semiconducting Quantum Dots. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2018; 5:1700684. [PMID: 29721417 PMCID: PMC5908380 DOI: 10.1002/advs.201700684] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/14/2017] [Indexed: 05/19/2023]
Abstract
The increasing demand for sustainable and environmentally benign energy has stimulated intense research to establish highly efficient photo-electrochemical (PEC) cells for direct solar-to-fuel conversion via water splitting. Light absorption, as the initial step of the catalytic process, is regarded as the foundation of establishing highly efficient PEC systems. To make full use of visible light, sensitization on photoelectrodes using either molecular dyes or semiconducting quantum dots provides a promising method. In this field, however, there remain many fundamental issues to be solved, which need in-depth study. Here, fundamental knowledge of PEC systems is introduced to enable readers a better understanding of this field. Then, the development history and current state in both molecular dye- and quantum dot-sensitized photocathodes for PEC water splitting are discussed. A systematical comparison between the two systems has been made. Special emphasis is placed on the research of quantum dot-sensitized photocathodes, which have shown superiority in both efficiency and durability towards PEC water splitting at the present stage. Finally, the opportunities and challenges in the future for sensitized PEC water-splitting systems are proposed.
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Affiliation(s)
- Hao‐Lin Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic MaterialsTechnical Institute of Physics and ChemistryThe Chinese Academy of SciencesBeijing100190P. R. China
- School of Future TechnologyUniversity of Chinese Academy of SciencesBeijing100049P. R. China
| | - Xu‐Bing Li
- Key Laboratory of Photochemical Conversion and Optoelectronic MaterialsTechnical Institute of Physics and ChemistryThe Chinese Academy of SciencesBeijing100190P. R. China
- School of Future TechnologyUniversity of Chinese Academy of SciencesBeijing100049P. R. China
| | - Chen‐Ho Tung
- Key Laboratory of Photochemical Conversion and Optoelectronic MaterialsTechnical Institute of Physics and ChemistryThe Chinese Academy of SciencesBeijing100190P. R. China
- School of Future TechnologyUniversity of Chinese Academy of SciencesBeijing100049P. R. China
| | - Li‐Zhu Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic MaterialsTechnical Institute of Physics and ChemistryThe Chinese Academy of SciencesBeijing100190P. R. China
- School of Future TechnologyUniversity of Chinese Academy of SciencesBeijing100049P. R. China
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17
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Sadeghi SM, Wing WJ, Gutha RR, Wilt JS, Wu JZ. Balancing silicon/aluminum oxide junctions for super-plasmonic emission enhancement of quantum dots via plasmonic metafilms. NANOSCALE 2018; 10:4825-4832. [PMID: 29473074 DOI: 10.1039/c7nr09396a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We study the impact of structural features of Si/Al oxide junctions on metal-oxide plasmonic metafilms formed via placing such junctions in close vicinity of an Au/Si Schottky barrier. The emission intensity and dynamics of colloidal semiconductor quantum dots deposited on such metafilms are investigated, while the surface morphology and structural compositions of the Si/Al oxide junction are controlled. The results show the conditions wherein the Si/Al oxide junction can reshape the impact of plasmonic effects, allowing it to increase the lifetimes of excitons. Under these conditions, the plasmonic metafilms can quarantine excitons against the fluctuating trap environments of the quantum dots, offering super-plasmonic emission enhancement that includes enhancement of the spontaneous emission decay rate combined with the suppression of Auger decay.
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Affiliation(s)
- Seyed M Sadeghi
- Department of Physics and Astronomy, University of Alabama in Huntsville, Huntsville, Alabama 35899, USA.
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18
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Gao W, Zhai G, Zhang C, Shao Z, Zheng L, Zhang Y, Yang Y, Li X, Liu X, Xu B. Towards understanding the initial performance improvement of PbS quantum dot solar cells upon short-term air exposure. RSC Adv 2018; 8:15149-15157. [PMID: 35541328 PMCID: PMC9080000 DOI: 10.1039/c8ra01422a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 04/15/2018] [Indexed: 01/29/2023] Open
Abstract
An initial improvement in performance of PbS quantum dot solar cells composed of one thick layer of PbS quantum dots (QDs) treated with tetrabutylammonium iodide (PbS–TBAI) and one thin layer of PbS QDs capped with 1,2-ethanedithiol (PbS–EDT) over short-term air exposure is widely observed. However, the underlying mechanisms still remain elusive. In the work, we sought to understand the mechanisms as well as their physicochemical origins using a combination of X-ray photoelectron spectroscopy (XPS) and various electronic measurements. It is found that the PbS–TBAI film plays a dominant role in the initial device performance improvement compared with the PbS–EDT film. The PbS–TBAI film is compensation doped upon short-term air exposure (one to three days) owing to the increase of Pb–O and/or Pb–OH species, enabling its energy band to align better with the electron transport layer for more efficient charge extraction. Moreover, it is demonstrated that the short-term air exposure is capable of reducing defects in the devices and improving the diode quality, resulting in an initial increase in device performance. This work contributes to the fundamental understanding of the surface chemistry changes of PbS quantum dots treated by different ligands over air-exposure and the role of surface chemistry of quantum dots in optimizing their photovoltaic performance. The mechanism at play that underpins the effect of short-term air exposure on the initial performance improvement of quantum dot solar cells is investigated.![]()
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19
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Solvent Engineering for High-Performance PbS Quantum Dots Solar Cells. NANOMATERIALS 2017; 7:nano7080201. [PMID: 28788077 PMCID: PMC5575683 DOI: 10.3390/nano7080201] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 07/18/2017] [Accepted: 07/25/2017] [Indexed: 11/17/2022]
Abstract
PbS colloidal quantum dots (CQDs) solar cells have already demonstrated very impressive advances in recent years due to the development of many different techniques to tailor the interface morphology and compactness in PbS CQDs thin film. Here, n-hexane, n-octane, n-heptane, isooctane and toluene or their hybrids are for the first time introduced as solvent for comparison of the dispersion of PbS CQDs. PbS CQDs solar cells with the configuration of PbS/TiO₂ heterojunction are then fabricated by using different CQDs solution under ambient conditions. The performances of the PbS CQDs solar cells are found to be tuned by changing solvent and its content in the PbS CQDs solution. The best device could show a power conversion efficiency (PCE) of 7.64% under AM 1.5 G illumination at 100 mW cm-2 in a n-octane/isooctane (95%/5% v/v) hybrid solvent scheme, which shows a ~15% improvement compared to the control devices. These results offer important insight into the solvent engineering of high-performance PbS CQDs solar cells.
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20
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Kim T, Palmiano E, Liang RZ, Hu H, Murali B, Kirmani AR, Firdaus Y, Gao Y, Sheikh A, Yuan M, Mohammed OF, Hoogland S, Beaujuge PM, Sargent EH, Amassian A. Hybrid tandem quantum dot/organic photovoltaic cells with complementary near infrared absorption. APPLIED PHYSICS LETTERS 2017; 110:223903. [PMID: 28652643 PMCID: PMC5453788 DOI: 10.1063/1.4984023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/10/2017] [Indexed: 05/13/2023]
Abstract
Monolithically integrated hybrid tandem solar cells that effectively combine solution-processed colloidal quantum dot (CQD) and organic bulk heterojunction subcells to achieve tandem performance that surpasses the individual subcell efficiencies have not been demonstrated to date. In this work, we demonstrate hybrid tandem cells with a low bandgap PbS CQD subcell harvesting the visible and near-infrared photons and a polymer:fullerene-poly (diketopyrrolopyrrole-terthiophene) (PDPP3T):[6,6]-phenyl-C60-butyric acid methyl ester (PC61BM)-top cell absorbing effectively the red and near-infrared photons of the solar spectrum in a complementary fashion. The two subcells are connected in series via an interconnecting layer (ICL) composed of a metal oxide layer, a conjugated polyelectrolyte, and an ultrathin layer of Au. The ultrathin layer of Au forms nano-islands in the ICL, reducing the series resistance, increasing the shunt resistance, and enhancing the device fill-factor. The hybrid tandems reach a power conversion efficiency (PCE) of 7.9%, significantly higher than the PCE of the corresponding individual single cells, representing one of the highest efficiencies reported to date for hybrid tandem solar cells based on CQD and polymer subcells.
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Affiliation(s)
- Taesoo Kim
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), and Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Elenita Palmiano
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada
| | - Ru-Ze Liang
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), and Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Hanlin Hu
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), and Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Banavoth Murali
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), and Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Ahmad R Kirmani
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), and Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Yuliar Firdaus
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), and Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Yangqin Gao
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), and Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Arif Sheikh
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), and Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Mingjian Yuan
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada
| | - Omar F Mohammed
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), and Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Sjoerd Hoogland
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada
| | - Pierre M Beaujuge
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), and Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Edward H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada
| | - Aram Amassian
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), and Physical Science and Engineering Division, Thuwal 23955-6900, Saudi Arabia
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21
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Reinhart CC, Johansson E. Colloidal 3-Mercaptopropionic Acid Capped Lead Sulfide Quantum Dots in a Low Boiling Point Solvent. J Am Chem Soc 2017; 139:5827-5835. [PMID: 28394592 DOI: 10.1021/jacs.7b00158] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Colloidal 3-mercaptopropionic acid (3-MPA) capped lead sulfide quantum dots were prepared in a variety of organic solvents stabilized with a quaternary ammonium halide salt. The stabilized colloids' optical properties were studied through optical absorption and emission spectroscopy and found to be dependent on both the concentration of a new ligand and stabilizer, and sample age. Nanocrystal ligand chemistry was studied through a combination of 1H NMR and two-dimensional Nuclear Overhauser Effect Spectroscopy (NOESY) which revealed full displacement of the original oleate ligand to form a dynamically exchanging ligand shell. The colloids were studied optically and via NMR as they aged and revealed a quantitative conversion of monomeric 3-mercaptopropionic acid to its dimer, dithiodipropionic acid (dTdPA).
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Affiliation(s)
- Chase C Reinhart
- Department of Chemistry, Portland State University , 1719 SW 10th Avenue, Portland, Oregon 97201, United States
| | - Erik Johansson
- Department of Chemistry, Portland State University , 1719 SW 10th Avenue, Portland, Oregon 97201, United States
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22
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Zhao K, Khan HU, Li R, Hu H, Amassian A. Carrier Transport Enhancement in Conjugated Polymers through Interfacial Self-Assembly of Solution-State Aggregates. ACS APPLIED MATERIALS & INTERFACES 2016; 8:19649-19657. [PMID: 27410517 DOI: 10.1021/acsami.6b04508] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We demonstrate that local and long-range orders of poly(3-hexylthiophene) (P3HT) semicrystalline films can be synergistically improved by combining chemical functionalization of the substrate with solution-state disentanglement and preaggregation of P3HT in a θ solvent, leading to a very significant enhancement of the field effect carrier mobility. The preaggregation and surface functionalization effects combine to enhance the carrier mobility nearly 100-fold as compared with standard film preparation by spin-coating, and nearly 10-fold increase over the benefits of preaggregation alone. In situ quartz crystal microbalance with dissipation (QCM-D) experiments reveal enhanced deposition of preaggregates on surfaces modified with an alkyl-terminated self-assembled monolayer (SAM) in comparison to unaggregated polymer chains in the same conditions. Additional measurements reveal the combined preaggregation and surface functionalization significantly enhances local order of the conjugated polymer through planarization and extension of the conjugated backbone of the polymer which clearly translate to significant improvements of carrier transport at the semiconductor-dielectric interface in organic thin film transistors. This study points to opportunities in combining complementary routes, such as well-known preaggregation with substrate chemical functionalization, to enhance the polymer self-assembly and improve its interfacial order with benefits for transport properties.
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Affiliation(s)
- Kui Zhao
- King Abdullah University of Science and Technology (KAUST) , KAUST Solar Center (KSC), and Division of Physical Sciences and Engineering, Thuwal 23955-6900, Saudi Arabia
| | - Hadayat Ullah Khan
- King Abdullah University of Science and Technology (KAUST) , KAUST Solar Center (KSC), and Division of Physical Sciences and Engineering, Thuwal 23955-6900, Saudi Arabia
| | - Ruipeng Li
- King Abdullah University of Science and Technology (KAUST) , KAUST Solar Center (KSC), and Division of Physical Sciences and Engineering, Thuwal 23955-6900, Saudi Arabia
| | - Hanlin Hu
- King Abdullah University of Science and Technology (KAUST) , KAUST Solar Center (KSC), and Division of Physical Sciences and Engineering, Thuwal 23955-6900, Saudi Arabia
| | - Aram Amassian
- King Abdullah University of Science and Technology (KAUST) , KAUST Solar Center (KSC), and Division of Physical Sciences and Engineering, Thuwal 23955-6900, Saudi Arabia
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23
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Balazs DM, Dirin DN, Fang HH, Protesescu L, ten Brink GH, Kooi BJ, Kovalenko MV, Loi MA. Counterion-Mediated Ligand Exchange for PbS Colloidal Quantum Dot Superlattices. ACS NANO 2015; 9:11951-9. [PMID: 26512884 PMCID: PMC4690194 DOI: 10.1021/acsnano.5b04547] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 10/29/2015] [Indexed: 05/17/2023]
Abstract
In the past years, halide capping became one of the most promising strategies to passivate the surface of colloidal quantum dots (CQDs) in thin films to be used for electronic and optoelectronic device fabrication. This is due to the convenient processing, strong n-type characteristics, and ambient stability of the devices. Here, we investigate the effect of three counterions (ammonium, methylammonium, and tetrabutylammonium) in iodide salts used for treating CQD thin films and shed light on the mechanism of the ligand exchange. We obtain two- and three-dimensional square-packed PbS CQD superlattices with epitaxial merging of nearest neighbor CQDs as a direct outcome of the ligand-exchange reaction and show that the order in the layer can be controlled by the nature of the counterion. Furthermore, we demonstrate that the acidity of the environment plays an important role in the substitution of the carboxylates by iodide ions at the surface of lead chalcogenide quantum dots. Tetrabutylammonium iodide shows lower reactivity compared to methylammonium and ammonium iodide due to the nonacidity of the cation, which eventually leads to higher order but also poorer carrier transport due to incomplete removal of the pristine ligands in the QD thin film. Finally, we show that single-step blade-coating and immersion in a ligand exchange solution such as the one containing methylammonium iodide can be used to fabricate well performing bottom-gate/bottom-contact PbS CQD field effect transistors with record subthreshold swing.
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Affiliation(s)
- Daniel M. Balazs
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Dmitry N. Dirin
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, Zürich 8093, Switzerland
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf 8600, Switzerland
| | - Hong-Hua Fang
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Loredana Protesescu
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, Zürich 8093, Switzerland
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf 8600, Switzerland
| | - Gert H. ten Brink
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Bart J. Kooi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Maksym V. Kovalenko
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir Prelog Weg 1, Zürich 8093, Switzerland
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf 8600, Switzerland
| | - Maria Antonietta Loi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
- Address correspondence to
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24
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Kagan CR, Murray CB. Charge transport in strongly coupled quantum dot solids. NATURE NANOTECHNOLOGY 2015; 10:1013-26. [PMID: 26551016 DOI: 10.1038/nnano.2015.247] [Citation(s) in RCA: 237] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 09/21/2015] [Indexed: 05/20/2023]
Abstract
The emergence of high-mobility, colloidal semiconductor quantum dot (QD) solids has triggered fundamental studies that map the evolution from carrier hopping through localized quantum-confined states to band-like charge transport in delocalized and hybridized states of strongly coupled QD solids, in analogy with the construction of solids from atoms. Increased coupling in QD solids has led to record-breaking performance in QD devices, such as electronic transistors and circuitry, optoelectronic light-emitting diodes, photovoltaic devices and photodetectors, and thermoelectric devices. Here, we review the advances in synthesis, assembly, ligand treatments and doping that have enabled high-mobility QD solids, as well as the experiments and theory that depict band-like transport in the QD solid state. We also present recent QD devices and discuss future prospects for QD materials and device design.
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Affiliation(s)
- Cherie R Kagan
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Christopher B Murray
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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25
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Choi H, Song JH, Jang J, Mai XD, Kim S, Jeong S. High performance of PbSe/PbS core/shell quantum dot heterojunction solar cells: short circuit current enhancement without the loss of open circuit voltage by shell thickness control. NANOSCALE 2015; 7:17473-17481. [PMID: 26440646 DOI: 10.1039/c5nr03309h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We fabricated heterojunction solar cells with PbSe/PbS core shell quantum dots and studied the precisely controlled PbS shell thickness dependency in terms of optical properties, electronic structure, and solar cell performances. When the PbS shell thickness increases, the short circuit current density (JSC) increases from 6.4 to 11.8 mA cm(-2) and the fill factor (FF) enhances from 30 to 49% while the open circuit voltage (VOC) remains unchanged at 0.46 V even with the decreased effective band gap. We found that the Fermi level and the valence band maximum level remain unchanged in both the PbSe core and PbSe/PbS core/shell with a less than 1 nm thick PbS shell as probed via ultraviolet photoelectron spectroscopy (UPS). The PbS shell reduces their surface trap density as confirmed by relative quantum yield measurements. Consequently, PbS shell formation on the PbSe core mitigates the trade-off relationship between the open circuit voltage and the short circuit current density. Finally, under the optimized conditions, the PbSe core with a 0.9 nm thick shell yielded a power conversion efficiency of 6.5% under AM 1.5.
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Affiliation(s)
- Hyekyoung Choi
- Nano-Mechanical Systems Research Division, Korea Institute of Machinery and Materials (KIMM), Daejeon, 305-343, Republic of Korea.
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26
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Carey GH, Yuan M, Comin R, Voznyy O, Sargent EH. Cleavable Ligands Enable Uniform Close Packing in Colloidal Quantum Dot Solids. ACS APPLIED MATERIALS & INTERFACES 2015; 7:21995-22000. [PMID: 26378717 DOI: 10.1021/acsami.5b06890] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Uniform close packing in colloidal quantum dot solids is critical for high-optical density, high-mobility optoelectronic devices. A hybrid-ligand strategy is developed, combining the advantages of solid state and solution-phase ligand exchanges. This strategy uses a medium length thioamide ligand that is readily cleaved in a single chemical treatment, leading to quantum dot solids with uniformly packed domains 3 times larger than those observed in ligand-exchanged films.
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Affiliation(s)
- Graham H Carey
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
| | - Mingjian Yuan
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
| | - Riccardo Comin
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
| | - Oleksandr Voznyy
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
| | - Edward H Sargent
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
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27
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Wu H, Zhang X, Zhang Y, Yan L, Gao W, Zhang T, Wang Y, Zhao J, Yu WW. Colloidal PbSe Solar Cells with Molybdenum Oxide Modified Graphene Anodes. ACS APPLIED MATERIALS & INTERFACES 2015; 7:21082-21088. [PMID: 26355262 DOI: 10.1021/acsami.5b03894] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
With good electrical conductivity, optical transparency, and mechanical compliance, graphene films have shown great potential in application for photovoltaic devices as electrodes. However, photovoltaic devices employing graphene anodes usually suffer from poor hole collection efficiency because of the mismatch of energy levels between the anode and light-harvesting layers. Here, a simple solution treatment and a low-cost solution-processed molybdenum oxide (MoOx) film were used to modify the work function of graphene and the interfacial morphology, respectively, yielding highly efficient hole transfer. As a result, the graphene/MoOx anodes demonstrated low surface roughness and high electrical conductivity. Using the graphene/MoOx anodes in PbSe nanocrystal solar cells, we achieved 1 sun power conversion efficiency of 3.56%. Compared to the control devices with indium tin oxide anodes, the graphene/MoOx-based devices show excellent performance, demonstrating the great potential of the graphene/MoOx anodes for use in optoelectronics.
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Affiliation(s)
- Hua Wu
- College of Material Science and Engineering, Qingdao University of Science and Technology , Qingdao 266042, China
| | | | | | | | | | | | | | - Jun Zhao
- Department of Chemistry and Physics, Louisiana State University , Shreveport, Louisiana 71115, United States
| | - William W Yu
- College of Material Science and Engineering, Qingdao University of Science and Technology , Qingdao 266042, China
- Department of Chemistry and Physics, Louisiana State University , Shreveport, Louisiana 71115, United States
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28
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Böhm ML, Jellicoe TC, Rivett JPH, Sadhanala A, Davis NJLK, Morgenstern FSF, Gödel KC, Govindasamy J, Benson CGM, Greenham NC, Ehrler B. Size and Energy Level Tuning of Quantum Dot Solids via a Hybrid Ligand Complex. J Phys Chem Lett 2015; 6:3510-3514. [PMID: 27120686 DOI: 10.1021/acs.jpclett.5b01751] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The performance of quantum dots (QDs) in optoelectronic devices suffers as a result of sub-bandgap states induced by the large fraction of atoms on the surface of QDs. Recent progress in passivating these surface states with thiol ligands and halide ions has led to competitive efficiencies. Here, we apply a hybrid ligand mixture to passivate PbSe QD sub-bandgap tail states via a low-temperature, solid-state ligand exchange. We show that this ligand mixture allows tuning of the energy levels and the physical QD size in the solid state during film formation. We hereby present a novel, postsynthetic path to tune the properties of QD films.
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Affiliation(s)
- Marcus L Böhm
- Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Tom C Jellicoe
- Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Jasmine P H Rivett
- Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Aditya Sadhanala
- Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Nathaniel J L K Davis
- Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Frederik S F Morgenstern
- Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Karl C Gödel
- Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Jayamurugan Govindasamy
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Callum G M Benson
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Neil C Greenham
- Cavendish Laboratory, University of Cambridge , J.J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Bruno Ehrler
- Center for Nanophotonics, FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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29
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Carey GH, Abdelhady AL, Ning Z, Thon SM, Bakr OM, Sargent EH. Colloidal Quantum Dot Solar Cells. Chem Rev 2015; 115:12732-63. [DOI: 10.1021/acs.chemrev.5b00063] [Citation(s) in RCA: 844] [Impact Index Per Article: 93.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Graham H. Carey
- Department
of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario M5S 3G4, Canada
| | - Ahmed L. Abdelhady
- Division of Physical Sciences and Engineering, Solar & Photovoltaics Engineering Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Zhijun Ning
- School
of Physical Science and Technology, ShanghaiTech University, 100 Haike
Road, Shanghai 201210, China
| | - Susanna M. Thon
- Department
of Electrical and Computer Engineering, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Osman M. Bakr
- Division of Physical Sciences and Engineering, Solar & Photovoltaics Engineering Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Edward H. Sargent
- Department
of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario M5S 3G4, Canada
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30
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Zhang G, Chen M, Zhang J, He B, Yang H, Yang B. Effective increase in the refractive index of novel transparent silicone hybrid films by introduction of functionalized silicon nanoparticles. RSC Adv 2015. [DOI: 10.1039/c5ra09668e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The refractive index of novel transparent silicone hybrid films can be effectively enhanced by introduction of functionalized silicon nanoparticles via a facile strategy.
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Affiliation(s)
- Guoyan Zhang
- Department of Materials Science and Engineering
- College of Engineering
- Peking University
- Beijing 100871
- P. R. China
| | - Mei Chen
- Department of Materials Science and Engineering
- College of Engineering
- Peking University
- Beijing 100871
- P. R. China
| | - Jibin Zhang
- State Key Laboratory of Supramolecular Structure and Materials
- College of Chemistry
- Jilin University
- Changchun
- P. R. China
| | - Baofeng He
- Department of Materials Science and Engineering
- College of Engineering
- Peking University
- Beijing 100871
- P. R. China
| | - Huai Yang
- Department of Materials Science and Engineering
- College of Engineering
- Peking University
- Beijing 100871
- P. R. China
| | - Bai Yang
- State Key Laboratory of Supramolecular Structure and Materials
- College of Chemistry
- Jilin University
- Changchun
- P. R. China
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31
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Carey GH, Kramer IJ, Kanjanaboos P, Moreno-Bautista G, Voznyy O, Rollny L, Tang JA, Hoogland S, Sargent EH. Electronically active impurities in colloidal quantum dot solids. ACS NANO 2014; 8:11763-11769. [PMID: 25376698 DOI: 10.1021/nn505343e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Colloidal quantum dot films have seen rapid progress as active materials in photodetection, light emission, and photovoltaics. Their processing from the solution phase makes them an attractive option for these applications due to the expected cost reductions associated with liquid-phase material deposition. Colloidally stable nanoparticles capped using long, insulating aliphatic ligands are used to form semiconducting, insoluble films via a solid-state ligand exchange in which the original ligands are replaced with short bifunctional ligands. Here we show that this ligand exchange can have unintended and undesired side effects: a high molecular weight complex can form, containing both lead oleate and the shorter conductive ligand, and this poorly soluble complex can end up embedded within the colloidal quantum dot (CQD) active layer. We further show that, by adding an acidic treatment during film processing, we can break up and wash away these complexes, producing a higher quality CQD solid. The improved material leads to photovoltaic devices with reduced series resistance and enhanced fill factor relative to controls employing previously reported CQD solids.
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Affiliation(s)
- Graham H Carey
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
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32
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Ning Z, Dong H, Zhang Q, Voznyy O, Sargent EH. Solar cells based on inks of n-type colloidal quantum dots. ACS NANO 2014; 8:10321-7. [PMID: 25225786 DOI: 10.1021/nn503569p] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
New inorganic ligands including halide anions have significantly accelerated progress in colloidal quantum dot (CQD) photovoltaics in recent years. All such device reports to date have relied on halide treatment during solid-state ligand exchanges or on co-treatment of long-aliphatic-ligand-capped nanoparticles in the solution phase. Here we report solar cells based on a colloidal quantum dot ink that is capped using halide-based ligands alone. By judicious choice of solvents and ligands, we developed a CQD ink from which a homogeneous and thick colloidal quantum dot solid is applied in a single step. The resultant films display an n-type character, making it suitable as a key component in a solar-converting device. We demonstrate two types of quantum junction devices that exploit these iodide-ligand-based inks. We achieve solar power conversion efficiencies of 6% using this class of colloids.
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Affiliation(s)
- Zhijun Ning
- Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada
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