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Li C, Wang X, Bi E, Jiang F, Park SM, Li Y, Chen L, Wang Z, Zeng L, Chen H, Liu Y, Grice CR, Abudulimu A, Chung J, Xian Y, Zhu T, Lai H, Chen B, Ellingson RJ, Fu F, Ginger DS, Song Z, Sargent EH, Yan Y. Rational design of Lewis base molecules for stable and efficient inverted perovskite solar cells. Science 2023; 379:690-694. [PMID: 36795809 DOI: 10.1126/science.ade3970] [Citation(s) in RCA: 57] [Impact Index Per Article: 57.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 01/13/2023] [Indexed: 02/18/2023]
Abstract
Lewis base molecules that bind undercoordinated lead atoms at interfaces and grain boundaries (GBs) are known to enhance the durability of metal halide perovskite solar cells (PSCs). Using density functional theory calculations, we found that phosphine-containing molecules have the strongest binding energy among members of a library of Lewis base molecules studied herein. Experimentally, we found that the best inverted PSC treated with 1,3-bis(diphenylphosphino)propane (DPPP), a diphosphine Lewis base that passivates, binds, and bridges interfaces and GBs, retained a power conversion efficiency (PCE) slightly higher than its initial PCE of ~23% after continuous operation under simulated AM1.5 illumination at the maximum power point and at ~40°C for >3500 hours. DPPP-treated devices showed a similar increase in PCE after being kept under open-circuit conditions at 85°C for >1500 hours.
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Affiliation(s)
- Chongwen Li
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
| | - Xiaoming Wang
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
| | - Enbing Bi
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
| | - Fangyuan Jiang
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - So Min Park
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada
| | - You Li
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
| | - Lei Chen
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
| | - Zaiwei Wang
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada
| | - Lewei Zeng
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada
| | - Hao Chen
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada
| | - Yanjiang Liu
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada
| | - Corey R Grice
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
- Center for Materials and Sensors Characterization, The University of Toledo, Toledo, OH 43606, USA
| | - Abasi Abudulimu
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
| | - Jaehoon Chung
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
| | - Yeming Xian
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
| | - Tao Zhu
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
| | - Huagui Lai
- Laboratory for Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland
| | - Bin Chen
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
| | - Randy J Ellingson
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
| | - Fan Fu
- Laboratory for Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland
| | - David S Ginger
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Zhaoning Song
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
| | - Edward H Sargent
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Yanfa Yan
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA
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2
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Jamarkattel MK, Mathew X, Phillips AB, Bastola E, Subedi KK, Alfadhili FK, Abudulimu A, Friedl JD, Awni RA, Li DB, Razooqi MA, Koirala P, Collins RW, Yan Y, Ellingson RJ, Heben MJ. Reduced Recombination and Improved Performance of CdSe/CdTe Solar Cells due to Cu Migration Induced by Light Soaking. ACS Appl Mater Interfaces 2022; 14:19644-19651. [PMID: 35451818 DOI: 10.1021/acsami.1c23937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The performance of CdTe solar cells has advanced impressively in recent years with the incorporation of Se. Instabilities associated with light soaking and copper reorganization have been extensively examined for the previous generation of CdS/CdTe solar cells, but instabilities in Cu-doped Se-alloyed CdTe devices remain relatively unexplored. In this work, we fabricated a range of CdSe/CdTe solar cells by sputtering CdSe layers with thicknesses of 100, 120, 150, 180, and 200 nm on transparent oxide-coated glass and then depositing CdTe by close-spaced sublimation. After CdCl2 annealing, Cu-doping, and back metal deposition, a variety of analyses were performed both before and after light soaking to understand the changes in device performance. The device efficiency was degraded with light soaking in most cases, but devices fabricated with a CdSe layer thickness of 120 nm showed reasonably good efficiency initially (13.5%) and a dramatic improvement with light soaking (16.5%). The efficiency improvement is examined within the context of Cu ion reorganization that is well known for CdS/CdTe devices. Low-temperature photoluminescence data and Voc versus temperature measurements indicate a reduction in nonradiative recombination due to the passivation of defects and defect complexes in the graded CdSexTe1-x layer.
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Affiliation(s)
- Manoj K Jamarkattel
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Xavier Mathew
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
- Instituto de Energías Renovables, Universidad Nacional Autónoma de México, Temixco, Morelos 62580, Mexico
| | - Adam B Phillips
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Ebin Bastola
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Kamala Khanal Subedi
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Fadhil K Alfadhili
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Abasi Abudulimu
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Jared D Friedl
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Rasha A Awni
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Deng-Bing Li
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Mohammed A Razooqi
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Prakash Koirala
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Robert W Collins
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Yanfa Yan
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Randy J Ellingson
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
| | - Michael J Heben
- Wright Center for Photovoltaic Innovation and Commercialization, Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
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Bista SS, Li DB, Awni RA, Song Z, Subedi KK, Shrestha N, Rijal S, Neupane S, Grice CR, Phillips AB, Ellingson RJ, Heben M, Li JV, Yan Y. Effects of Cu Precursor on the Performance of Efficient CdTe Solar Cells. ACS Appl Mater Interfaces 2021; 13:38432-38440. [PMID: 34347421 DOI: 10.1021/acsami.1c11784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Copper (Cu) incorporation is a key process for fabricating efficient CdTe-based thin-film solar cells and has been used in CdTe-based solar cell module manufacturing. Here, we investigate the effects of different Cu precursors on the performance of CdTe-based thin-film solar cells by incorporating Cu using a metallic Cu source (evaporated Cu) and ionic Cu sources (solution-processed cuprous chloride (CuCl) and copper chloride (CuCl2)). We find that ionic Cu precursors offer much better control in Cu diffusion than the metallic Cu precursor, producing better front junction quality, lower back-barrier heights, and better bulk defect property. Finally, outperforming power conversion efficiencies of 17.2 and 17.5% are obtained for devices with cadmium sulfide and zinc magnesium oxide as the front window layers, respectively, which are among the highest reported CdTe solar cells efficiencies. Our results suggest that an ionic Cu precursor is preferred as the dopant to fabricate efficient CdTe thin-film solar cells and modules.
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Affiliation(s)
- Sandip S Bista
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Deng-Bing Li
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Rasha A Awni
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Zhaoning Song
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Kamala K Subedi
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Niraj Shrestha
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Suman Rijal
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Sabin Neupane
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Corey R Grice
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Adam B Phillips
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Randy J Ellingson
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Michael Heben
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Jian V Li
- Department of Aeronautics and Astronautics, National Cheng Kung University, 70101 Tainan, Taiwan
| | - Yanfa Yan
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
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Alfadhili FK, Phillips AB, Subedi KK, Perkins CL, Halaoui AI, Jamarkattel MK, Anwar BM, Liyanage GK, Li DB, Grice CR, Yan Y, Ellingson RJ, Heben MJ. Back-Surface Passivation of CdTe Solar Cells Using Solution-Processed Oxidized Aluminum. ACS Appl Mater Interfaces 2020; 12:51337-51343. [PMID: 33146989 DOI: 10.1021/acsami.0c12800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Although back-surface passivation plays an important role in high-efficiency photovoltaics, it has not yet been definitively demonstrated for CdTe. Here, we present a solution-based process, which achieves passivation and improved electrical performance when very small amounts of oxidized Al3+ species are deposited at the back surface of CdTe devices. The open circuit voltage (Voc) is increased and the fill factor (FF) and photoconversion efficiency (PCE) are optimized when the total amount added corresponds to ∼1 monolayer, suggesting that the passivation is surface specific. Addition of further Al3+ species, present in a sparse alumina-like layer, causes the FF and PCE to drop as the interface layer becomes blocking to current flow. The optimized deposit increases the average baseline PCE for both Cu-free devices and devices where Cu is present as a dopant. The greatest improvement is found when the Al3+ species are deposited prior to the CdCl2 activation step and Cu is employed. In this case, the best-cell efficiency was improved from 12.6 to 14.4%. Time-resolved photoluminescence measurements at the back surface and quantum efficiency measurements performed at the maximum power point indicate that the performance enhancement is due to a reduction in the interface recombination current at the back surface.
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Affiliation(s)
- Fadhil K Alfadhili
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - Adam B Phillips
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - Kamala Khanal Subedi
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - Craig L Perkins
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Adam I Halaoui
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - Manoj K Jamarkattel
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - Bhuiyan M Anwar
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - Geethika K Liyanage
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - Deng-Bing Li
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - Corey R Grice
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - Yanfa Yan
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - Randy J Ellingson
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
| | - Michael J Heben
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
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Li DB, Song Z, Bista SS, Alfadhili FK, Awni RA, Shrestha N, Rhiannon D, Phillips AB, Heben MJ, Ellingson RJ, Yan F, Yan Y. CuSCN as the Back Contact for Efficient ZMO/CdTe Solar Cells. Materials (Basel) 2020; 13:ma13081991. [PMID: 32344645 PMCID: PMC7215694 DOI: 10.3390/ma13081991] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 11/22/2022]
Abstract
The replacement of traditional CdS with zinc magnesium oxide (ZMO) has been demonstrated as being helpful to boost power conversion efficiency of cadmium telluride (CdTe) solar cells to over 18%, due to the reduced interface recombination and parasitic light absorption by the buffer layer. However, due to the atmosphere sensitivity of ZMO film, the post treatments of ZMO/CdTe stacks, including CdCl2 treatment, back contact deposition, etc., which are critical for high-performance CdTe solar cells became crucial challenges. To realize the full potential of the ZMO buffer layer, plenty of investigations need to be accomplished. Here, copper thiocyanate (CuSCN) is demonstrated to be a suitable back-contact material with multi-advantages for ZMO/CdTe solar cells. Particularly, ammonium hydroxide as the solvent for CuSCN deposition shows no detrimental impact on the ZMO layer during the post heat treatment. The post annealing temperature as well as the thickness of CuSCN films are investigated. Finally, a champion power conversion efficiency of 16.7% is achieved with an open-circuit voltage of 0.857 V, a short-circuit current density of 26.2 mA/cm2, and a fill factor of 74.0%.
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Affiliation(s)
- Deng-Bing Li
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, OH 43606, USA; (D.-B.L.); (Z.S.); (S.S.B.); (F.K.A.); (R.A.A.); (N.S.); (A.B.P.); (M.J.H.); (R.J.E.)
| | - Zhaoning Song
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, OH 43606, USA; (D.-B.L.); (Z.S.); (S.S.B.); (F.K.A.); (R.A.A.); (N.S.); (A.B.P.); (M.J.H.); (R.J.E.)
| | - Sandip S. Bista
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, OH 43606, USA; (D.-B.L.); (Z.S.); (S.S.B.); (F.K.A.); (R.A.A.); (N.S.); (A.B.P.); (M.J.H.); (R.J.E.)
| | - Fadhil K. Alfadhili
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, OH 43606, USA; (D.-B.L.); (Z.S.); (S.S.B.); (F.K.A.); (R.A.A.); (N.S.); (A.B.P.); (M.J.H.); (R.J.E.)
| | - Rasha A. Awni
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, OH 43606, USA; (D.-B.L.); (Z.S.); (S.S.B.); (F.K.A.); (R.A.A.); (N.S.); (A.B.P.); (M.J.H.); (R.J.E.)
| | - Niraj Shrestha
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, OH 43606, USA; (D.-B.L.); (Z.S.); (S.S.B.); (F.K.A.); (R.A.A.); (N.S.); (A.B.P.); (M.J.H.); (R.J.E.)
| | - DeMilt Rhiannon
- Ottawa Hills Junior/senior high school, Ottawa Hills Local Schools, Ottawa Hills, OH 43606, USA;
| | - Adam B. Phillips
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, OH 43606, USA; (D.-B.L.); (Z.S.); (S.S.B.); (F.K.A.); (R.A.A.); (N.S.); (A.B.P.); (M.J.H.); (R.J.E.)
| | - Michael J. Heben
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, OH 43606, USA; (D.-B.L.); (Z.S.); (S.S.B.); (F.K.A.); (R.A.A.); (N.S.); (A.B.P.); (M.J.H.); (R.J.E.)
| | - Randy J. Ellingson
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, OH 43606, USA; (D.-B.L.); (Z.S.); (S.S.B.); (F.K.A.); (R.A.A.); (N.S.); (A.B.P.); (M.J.H.); (R.J.E.)
| | - Feng Yan
- Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, AL 35487, USA;
| | - Yanfa Yan
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, OH 43606, USA; (D.-B.L.); (Z.S.); (S.S.B.); (F.K.A.); (R.A.A.); (N.S.); (A.B.P.); (M.J.H.); (R.J.E.)
- Correspondence:
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6
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Shrestha N, Song Z, Chen C, Bastola E, Wang X, Yan Y, Ellingson RJ. Charge Compensating Defects in Methylammonium Lead Iodide Perovskite Suppressed by Formamidinium Inclusion. J Phys Chem Lett 2020; 11:121-128. [PMID: 31820989 DOI: 10.1021/acs.jpclett.9b03234] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Temperature-dependent photoluminescence (PL) spectroscopy measurements have been performed over a range from 9 K to room temperature on polycrystalline methylammonium (MA)/formamidinium (FA) lead iodide (MA1-xFAxPbI3) perovskite thin films. Our low-temperature PL analysis reveals the existence of charge compensating defects in MAPbI3, which may explain the lower net free carrier concentration in MAPbI3 perovskite. More interestingly, we observe the suppression of the PL emission associated with the charged defects by appropriate FA inclusion. Furthermore, FA incorporation into MAPbI3 has been found to slow the phase transformation of MA1-xFAxPbI3 from orthorhombic to tetragonal phase, which occurs with increasing temperature. Our analyses of the FA concentration's impact on defect density and structural phase transformation provide beneficial insights that improve the understanding of the photovoltaic properties and application of organic-inorganic metal halide perovskites.
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Affiliation(s)
- Niraj Shrestha
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization , University of Toledo , Toledo , Ohio 43606 , United States
| | - Zhaoning Song
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization , University of Toledo , Toledo , Ohio 43606 , United States
| | - Cong Chen
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization , University of Toledo , Toledo , Ohio 43606 , United States
| | - Ebin Bastola
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization , University of Toledo , Toledo , Ohio 43606 , United States
| | - Xiaoming Wang
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization , University of Toledo , Toledo , Ohio 43606 , United States
| | - Yanfa Yan
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization , University of Toledo , Toledo , Ohio 43606 , United States
| | - Randy J Ellingson
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization , University of Toledo , Toledo , Ohio 43606 , United States
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7
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Zhou J, Yin X, Dong Z, Ali A, Song Z, Shrestha N, Bista SS, Bao Q, Ellingson RJ, Yan Y, Tang W. Dithieno[3,2‐b:2′,3′‐d]pyrrole Cored p‐Type Semiconductors Enabling 20 % Efficiency Dopant‐Free Perovskite Solar Cells. Angew Chem Int Ed Engl 2019; 58:13717-13721. [DOI: 10.1002/anie.201905624] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Jie Zhou
- School of Chemical EngineeringNanjing University and Science and Technology Nanjing 210094 China
| | - Xinxing Yin
- School of Chemical EngineeringNanjing University and Science and Technology Nanjing 210094 China
| | - Zihao Dong
- School of Chemical EngineeringNanjing University and Science and Technology Nanjing 210094 China
| | - Amjad Ali
- School of Chemical EngineeringNanjing University and Science and Technology Nanjing 210094 China
| | - Zhaoning Song
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and CommercializationThe University of Toledo Toledo OH 43606 USA
| | - Niraj Shrestha
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and CommercializationThe University of Toledo Toledo OH 43606 USA
| | - Sandip Singh Bista
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and CommercializationThe University of Toledo Toledo OH 43606 USA
| | - Qinye Bao
- Key Laboratory of Polar Materials and DevicesDepartment of OptoelectronicsEast China Normal University Shanghai 200241 China
| | - Randy J. Ellingson
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and CommercializationThe University of Toledo Toledo OH 43606 USA
| | - Yanfa Yan
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and CommercializationThe University of Toledo Toledo OH 43606 USA
| | - Weihua Tang
- School of Chemical EngineeringNanjing University and Science and Technology Nanjing 210094 China
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8
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Zhou J, Yin X, Dong Z, Ali A, Song Z, Shrestha N, Bista SS, Bao Q, Ellingson RJ, Yan Y, Tang W. Dithieno[3,2‐b:2′,3′‐d]pyrrole Cored p‐Type Semiconductors Enabling 20 % Efficiency Dopant‐Free Perovskite Solar Cells. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201905624] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jie Zhou
- School of Chemical EngineeringNanjing University and Science and Technology Nanjing 210094 China
| | - Xinxing Yin
- School of Chemical EngineeringNanjing University and Science and Technology Nanjing 210094 China
| | - Zihao Dong
- School of Chemical EngineeringNanjing University and Science and Technology Nanjing 210094 China
| | - Amjad Ali
- School of Chemical EngineeringNanjing University and Science and Technology Nanjing 210094 China
| | - Zhaoning Song
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and CommercializationThe University of Toledo Toledo OH 43606 USA
| | - Niraj Shrestha
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and CommercializationThe University of Toledo Toledo OH 43606 USA
| | - Sandip Singh Bista
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and CommercializationThe University of Toledo Toledo OH 43606 USA
| | - Qinye Bao
- Key Laboratory of Polar Materials and DevicesDepartment of OptoelectronicsEast China Normal University Shanghai 200241 China
| | - Randy J. Ellingson
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and CommercializationThe University of Toledo Toledo OH 43606 USA
| | - Yanfa Yan
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and CommercializationThe University of Toledo Toledo OH 43606 USA
| | - Weihua Tang
- School of Chemical EngineeringNanjing University and Science and Technology Nanjing 210094 China
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9
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Song Z, Shrestha N, Watthage SC, Liyanage GK, Almutawah ZS, Ahangharnejhad RH, Phillips AB, Ellingson RJ, Heben MJ. Impact of Moisture on Photoexcited Charge Carrier Dynamics in Methylammonium Lead Halide Perovskites. J Phys Chem Lett 2018; 9:6312-6320. [PMID: 30336064 DOI: 10.1021/acs.jpclett.8b02595] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Organic-inorganic metal halide perovskites are notoriously unstable in humid environments. While many studies have revealed the morphology and crystal structure changes that accompany exposure to humidity, little is known about changes to the photophysics that accompany the degradation process. By combining in situ steady-state and time-resolved photoluminescence with Hall effect measurements, we examined the changes in the photoexcited carrier dynamics for methylammonium lead iodide (MAPbI3) and bromide (MAPbBr3) films exposed to nitrogen gas containing water vapor at 80% relative humidity. The changes in the photophysics of MAPbI3 interacting with water follow a four-stage process, consisting of surface passivation, free electron doping, interfacial hydration, and bulk hydration. In contrast, MAPbBr3 exhibits only features associated with the first two stages, which occur at a faster rate. Our results elucidate the degradation mechanisms of perovskite films in high humidity from the perspective of the photophysics, providing insights for how humidity affects the stability of the perovskite materials.
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Affiliation(s)
- Zhaoning Song
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy , University of Toledo , 2801 West Bancroft Street , Toledo , Ohio 43606 United States
| | - Niraj Shrestha
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy , University of Toledo , 2801 West Bancroft Street , Toledo , Ohio 43606 United States
| | - Suneth C Watthage
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy , University of Toledo , 2801 West Bancroft Street , Toledo , Ohio 43606 United States
| | - Geethika K Liyanage
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy , University of Toledo , 2801 West Bancroft Street , Toledo , Ohio 43606 United States
| | - Zahrah S Almutawah
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy , University of Toledo , 2801 West Bancroft Street , Toledo , Ohio 43606 United States
| | - Ramez H Ahangharnejhad
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy , University of Toledo , 2801 West Bancroft Street , Toledo , Ohio 43606 United States
| | - Adam B Phillips
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy , University of Toledo , 2801 West Bancroft Street , Toledo , Ohio 43606 United States
| | - Randy J Ellingson
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy , University of Toledo , 2801 West Bancroft Street , Toledo , Ohio 43606 United States
| | - Michael J Heben
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy , University of Toledo , 2801 West Bancroft Street , Toledo , Ohio 43606 United States
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10
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Shrestha N, Sapkota DR, Subedi KK, Pradhan P, Koirala P, Phillips AB, Collins RW, Heben MJ, Ellingson RJ. Identification of Defect Levels in Copper Indium Diselenide (CuInSe2) Thin Films via Photoluminescence Studies. ACTA ACUST UNITED AC 2018. [DOI: 10.1557/adv.2018.556] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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11
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Shrestha N, Grice CR, Bastola E, Liyanage GK, Phillips AB, Heben MJ, Yan Y, Ellingson RJ. Low Temperature Photoluminescence Spectroscopy of Defect and Interband Transitions in CdSexTe1-x Thin Films. ACTA ACUST UNITED AC 2018. [DOI: 10.1557/adv.2018.516] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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12
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Almutawah ZS, Watthage SC, Song Z, Ahangharnejhad RH, Subedi KK, Shrestha N, Phillips AB, Yan Y, Ellingson RJ, Heben MJ. Enhanced Grain Size and Crystallinity in CH3NH3PbI3 Perovskite Films by Metal Additives to the Single-Step Solution Fabrication Process. ACTA ACUST UNITED AC 2018. [DOI: 10.1557/adv.2018.413] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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Bastola E, Subedi KK, Bhandari KP, Ellingson RJ. Solution-processed Nanocrystal Based Thin Films as Hole Transport Materials in Cadmium Telluride Photovoltaics. ACTA ACUST UNITED AC 2018. [DOI: 10.1557/adv.2018.349] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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14
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Pradhan P, Aryal P, Attygalle D, Ibdah AR, Koirala P, Li J, Bhandari KP, Liyanage GK, Ellingson RJ, Heben MJ, Marsillac S, Collins RW, Podraza NJ. Real Time Spectroscopic Ellipsometry Analysis of First Stage CuIn 1-xGa xSe₂ Growth: Indium-Gallium Selenide Co-Evaporation. Materials (Basel) 2018; 11:ma11010145. [PMID: 29337931 PMCID: PMC5793643 DOI: 10.3390/ma11010145] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 01/10/2018] [Accepted: 01/10/2018] [Indexed: 11/16/2022]
Abstract
Real time spectroscopic ellipsometry (RTSE) has been applied for in-situ monitoring of the first stage of copper indium-gallium diselenide (CIGS) thin film deposition by the three-stage co-evaporation process used for fabrication of high efficiency thin film photovoltaic (PV) devices. The first stage entails the growth of indium-gallium selenide (In1-xGax)₂Se₃ (IGS) on a substrate of Mo-coated soda lime glass maintained at a temperature of 400 °C. This is a critical stage of CIGS deposition because a large fraction of the final film thickness is deposited, and as a result precise compositional control is desired in order to achieve the optimum performance of the resulting CIGS solar cell. RTSE is sensitive to monolayer level film growth processes and can provide accurate measurements of bulk and surface roughness layer thicknesses. These in turn enable accurate measurements of the bulk layer optical response in the form of the complex dielectric function ε = ε₁ - iε₂, spectra. Here, RTSE has been used to obtain the (ε₁, ε₂) spectra at the measurement temperature of 400 °C for IGS thin films of different Ga contents (x) deduced from different ranges of accumulated bulk layer thickness during the deposition process. Applying an analytical expression in common for each of the (ε₁, ε₂) spectra of these IGS films, oscillator parameters have been obtained in the best fits and these parameters in turn have been fitted with polynomials in x. From the resulting database of polynomial coefficients, the (ε₁, ε₂) spectra can be generated for any composition of IGS from the single parameter, x. The results have served as an RTSE fingerprint for IGS composition and have provided further structural information beyond simply thicknesses, for example information related to film density and grain size. The deduced IGS structural evolution and the (ε₁, ε₂) spectra have been interpreted as well in relation to observations from scanning electron microscopy, X-ray diffractometry and energy-dispersive X-ray spectroscopy profiling analyses. Overall the structural, optical and compositional analysis possible by RTSE has assisted in understanding the growth and properties of three stage CIGS absorbers for solar cells and shows future promise for enhancing cell performance through monitoring and control.
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Affiliation(s)
- Puja Pradhan
- Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA.
| | - Puruswottam Aryal
- Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA.
| | - Dinesh Attygalle
- Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA.
| | - Abdel-Rahman Ibdah
- Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA.
| | - Prakash Koirala
- Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA.
| | - Jian Li
- Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA.
| | - Khagendra P Bhandari
- Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA.
| | - Geethika K Liyanage
- Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA.
| | - Randy J Ellingson
- Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA.
| | - Michael J Heben
- Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA.
| | - Sylvain Marsillac
- Virginia Institute of Photovoltaics, Old Dominion University, Norfolk, VA 23529, USA.
| | - Robert W Collins
- Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA.
| | - Nikolas J Podraza
- Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA.
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15
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Watthage SC, Song Z, Shrestha N, Phillips AB, Liyanage GK, Roland PJ, Ellingson RJ, Heben MJ. Enhanced Grain Size, Photoluminescence, and Photoconversion Efficiency with Cadmium Addition during the Two-Step Growth of CH 3NH 3PbI 3. ACS Appl Mater Interfaces 2017; 9:2334-2341. [PMID: 28009167 DOI: 10.1021/acsami.6b12627] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Control over grain size and crystallinity is important for preparation of methylammonium lead iodide (MAPbI3) solar cells. We explore the effects of using small concentrations of Cd2+ and unusually high concentrations of methylammonium iodide during the growth of MAPbI3 in the two-step solution process. In addition to improved crystallinity and an enhancement in the size of the grains, time-resolved photoluminescence measurements indicated a dramatic increase in the carrier lifetime. As a result, devices constructed with the Cd-modified perovskites showed nearly a factor of 2 improvement in the power conversion efficiency (PCE) relative to similar devices prepared without Cd addition. The grains also showed a higher degree of orientation in the ⟨110⟩ direction, indicating a change in the growth mechanism, and the films were compact and smooth. We propose a Cd-modified film growth mechanism that invokes a critical role for low-dimensional Cd perovskites to explain the experimental observations.
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Affiliation(s)
- Suneth C Watthage
- Wright Center for Photovoltaics Innovation and Commercialization, School of Solar and Advanced Renewable Energy, Department of Physics and Astronomy, University of Toledo , Toledo, Ohio 43606, United States
| | - Zhaoning Song
- Wright Center for Photovoltaics Innovation and Commercialization, School of Solar and Advanced Renewable Energy, Department of Physics and Astronomy, University of Toledo , Toledo, Ohio 43606, United States
| | - Niraj Shrestha
- Wright Center for Photovoltaics Innovation and Commercialization, School of Solar and Advanced Renewable Energy, Department of Physics and Astronomy, University of Toledo , Toledo, Ohio 43606, United States
| | - Adam B Phillips
- Wright Center for Photovoltaics Innovation and Commercialization, School of Solar and Advanced Renewable Energy, Department of Physics and Astronomy, University of Toledo , Toledo, Ohio 43606, United States
| | - Geethika K Liyanage
- Wright Center for Photovoltaics Innovation and Commercialization, School of Solar and Advanced Renewable Energy, Department of Physics and Astronomy, University of Toledo , Toledo, Ohio 43606, United States
| | - Paul J Roland
- Wright Center for Photovoltaics Innovation and Commercialization, School of Solar and Advanced Renewable Energy, Department of Physics and Astronomy, University of Toledo , Toledo, Ohio 43606, United States
| | - Randy J Ellingson
- Wright Center for Photovoltaics Innovation and Commercialization, School of Solar and Advanced Renewable Energy, Department of Physics and Astronomy, University of Toledo , Toledo, Ohio 43606, United States
| | - Michael J Heben
- Wright Center for Photovoltaics Innovation and Commercialization, School of Solar and Advanced Renewable Energy, Department of Physics and Astronomy, University of Toledo , Toledo, Ohio 43606, United States
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16
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Song Z, Werner J, Shrestha N, Sahli F, De Wolf S, Niesen B, Watthage SC, Phillips AB, Ballif C, Ellingson RJ, Heben MJ. Probing Photocurrent Nonuniformities in the Subcells of Monolithic Perovskite/Silicon Tandem Solar Cells. J Phys Chem Lett 2016; 7:5114-5120. [PMID: 27973901 DOI: 10.1021/acs.jpclett.6b02415] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Perovskite/silicon tandem solar cells with high power conversion efficiencies have the potential to become a commercially viable photovoltaic option in the near future. However, device design and optimization is challenging because conventional characterization methods do not give clear feedback on the localized chemical and physical factors that limit performance within individual subcells, especially when stability and degradation is a concern. In this study, we use light beam induced current (LBIC) to probe photocurrent collection nonuniformities in the individual subcells of perovskite/silicon tandems. The choices of lasers and light biasing conditions allow efficiency-limiting effects relating to processing defects, optical interference within the individual cells, and the evolution of water-induced device degradation to be spatially resolved. The results reveal several types of microscopic defects and demonstrate that eliminating these and managing the optical properties within the multilayer structures will be important for future optimization of perovskite/silicon tandem solar cells.
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Affiliation(s)
- Zhaoning Song
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo , 2801 West Bancroft Street, Toledo, Ohio 43606 United States
| | - Jérémie Werner
- Institute of Microengineering (IMT), Photovoltaics and Thin-Film Electronics Laboratory (PV-Lab), Ecole Polytechnique Fédérale de Lausanne (EPFL) , Rue de la Maladière 71b, 2002 Neuchâtel, Switzerland
| | - Niraj Shrestha
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo , 2801 West Bancroft Street, Toledo, Ohio 43606 United States
| | - Florent Sahli
- Institute of Microengineering (IMT), Photovoltaics and Thin-Film Electronics Laboratory (PV-Lab), Ecole Polytechnique Fédérale de Lausanne (EPFL) , Rue de la Maladière 71b, 2002 Neuchâtel, Switzerland
| | - Stefaan De Wolf
- Institute of Microengineering (IMT), Photovoltaics and Thin-Film Electronics Laboratory (PV-Lab), Ecole Polytechnique Fédérale de Lausanne (EPFL) , Rue de la Maladière 71b, 2002 Neuchâtel, Switzerland
| | - Björn Niesen
- Institute of Microengineering (IMT), Photovoltaics and Thin-Film Electronics Laboratory (PV-Lab), Ecole Polytechnique Fédérale de Lausanne (EPFL) , Rue de la Maladière 71b, 2002 Neuchâtel, Switzerland
- CSEM, PV-Center , Jaquet-Droz 1, 2002 Neuchâtel, Switzerland
| | - Suneth C Watthage
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo , 2801 West Bancroft Street, Toledo, Ohio 43606 United States
| | - Adam B Phillips
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo , 2801 West Bancroft Street, Toledo, Ohio 43606 United States
| | - Christophe Ballif
- Institute of Microengineering (IMT), Photovoltaics and Thin-Film Electronics Laboratory (PV-Lab), Ecole Polytechnique Fédérale de Lausanne (EPFL) , Rue de la Maladière 71b, 2002 Neuchâtel, Switzerland
- CSEM, PV-Center , Jaquet-Droz 1, 2002 Neuchâtel, Switzerland
| | - Randy J Ellingson
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo , 2801 West Bancroft Street, Toledo, Ohio 43606 United States
| | - Michael J Heben
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo , 2801 West Bancroft Street, Toledo, Ohio 43606 United States
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17
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Yu Y, Wang C, Grice CR, Shrestha N, Chen J, Zhao D, Liao W, Cimaroli AJ, Roland PJ, Ellingson RJ, Yan Y. Improving the Performance of Formamidinium and Cesium Lead Triiodide Perovskite Solar Cells using Lead Thiocyanate Additives. ChemSusChem 2016; 9:3288-3297. [PMID: 27783456 DOI: 10.1002/cssc.201601027] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Indexed: 06/06/2023]
Abstract
Formamidinium lead triiodide (FAPbI3 ) is considered as an alternative to methylammonium lead triiodide (MAPbI3 ) because of its lower band gap and better thermal stability. However, owing to the large size of FA cations, it is difficult to synthesize high-quality FAPbI3 thin films without the formation of an undesirable yellow phase. Smaller sized cations, such as MA and Cs, have been successfully used to suppress the formation of the yellow phase. Whereas FA and MA lead triiodide perovskite solar cells (PVSCs) have achieved power conversion efficiencies (PCEs) higher than 20 %, the PCEs of formamidinium and cesium lead triiodide (FA1-x Csx PbI3 ) PVSCs have been only approximately 16.5 %. Herein, we report our examination of the main factors limiting the PCEs of (FA1-x Csx PbI3 ) PVSCs. We find that one of the main limiting factors could be the small grain sizes (≈120 nm), which leads to relatively short carrier lifetimes. We further find that adding a small amount of lead thiocyanate [Pb(SCN)2 ] to the precursors can enlarge the grain size of (FA1-x Csx PbI3 ) perovskite thin films and significantly increase carrier lifetimes. As a result, we are able to fabricate (FA1-x Csx PbI3 ) PVSCs with significantly improved open-circuit voltages and fill factors and, therefore, enhanced PCEs. With an optimal 0.5 mol % Pb(SCN)2 additive, the average PCE is increased from 16.18±0.50 (13.45±0.78) % to 18.16±0.54 (16.86±0.63) % for planar FA0.8 Cs0.2 PbI3 PVSCs if measured under reverse (forward) voltage scans. The champion cell registers a PCE of 19.57 (18.12) % if measured under a reverse (forward) voltage scan, which is comparable to that of the best-performing MA-containing planar FA-based lead halide PVSCs.
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Affiliation(s)
- Yue Yu
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, 43606, USA
| | - Changlei Wang
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, 43606, USA
| | - Corey R Grice
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, 43606, USA
| | - Niraj Shrestha
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, 43606, USA
| | - Jing Chen
- School of Electronic Science and Engineering, Southeast University, Nanjing, 210096, PR China
| | - Dewei Zhao
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, 43606, USA
| | - Weiqiang Liao
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, 43606, USA
| | - Alexander J Cimaroli
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, 43606, USA
| | - Paul J Roland
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, 43606, USA
| | - Randy J Ellingson
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, 43606, USA
| | - Yanfa Yan
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, 43606, USA
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18
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Huckaba AJ, Sanghyun P, Grancini G, Bastola E, Taek CK, Younghui L, Bhandari KP, Ballif C, Ellingson RJ, Nazeeruddin MK. Exceedingly Cheap Perovskite Solar Cells Using Iron Pyrite Hole Transport Materials. ChemistrySelect 2016. [DOI: 10.1002/slct.201601378] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Aron J. Huckaba
- Group for Molecular Engineering of Functional Materials, Institute of Chemical Sciences and Engineering, School of Basic Sciences; Ecole Polytechnique Fédérale de Lausanne Valais (EPFL-Valais); Rue de L'industrie 17 Sion CH- 1951 Switzerland
| | - Paek Sanghyun
- Group for Molecular Engineering of Functional Materials, Institute of Chemical Sciences and Engineering, School of Basic Sciences; Ecole Polytechnique Fédérale de Lausanne Valais (EPFL-Valais); Rue de L'industrie 17 Sion CH- 1951 Switzerland
| | - Giulia Grancini
- Group for Molecular Engineering of Functional Materials, Institute of Chemical Sciences and Engineering, School of Basic Sciences; Ecole Polytechnique Fédérale de Lausanne Valais (EPFL-Valais); Rue de L'industrie 17 Sion CH- 1951 Switzerland
| | - Ebin Bastola
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy; The University of Toledo; 2801 W. Bancroft Street Toledo, OH 43606 USA
| | - Cho Kyung Taek
- Group for Molecular Engineering of Functional Materials, Institute of Chemical Sciences and Engineering, School of Basic Sciences; Ecole Polytechnique Fédérale de Lausanne Valais (EPFL-Valais); Rue de L'industrie 17 Sion CH- 1951 Switzerland
| | - Lee Younghui
- Group for Molecular Engineering of Functional Materials, Institute of Chemical Sciences and Engineering, School of Basic Sciences; Ecole Polytechnique Fédérale de Lausanne Valais (EPFL-Valais); Rue de L'industrie 17 Sion CH- 1951 Switzerland
| | - Khagendra P. Bhandari
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy; The University of Toledo; 2801 W. Bancroft Street Toledo, OH 43606 USA
| | - Christophe Ballif
- Institute of Microengineering (IMT), Photovoltaics and Thin-Film Electronics Laboratory; Ecole Polytechnique Fédérale de Lausanne (EPFL); Rue de la Maladière 71b Neuchâtel CH- 2002 Switzerland
| | - Randy J. Ellingson
- Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy; The University of Toledo; 2801 W. Bancroft Street Toledo, OH 43606 USA
- Institute of Microengineering (IMT), Photovoltaics and Thin-Film Electronics Laboratory; Ecole Polytechnique Fédérale de Lausanne (EPFL); Rue de la Maladière 71b Neuchâtel CH- 2002 Switzerland
| | - Mohammad Khaja Nazeeruddin
- Group for Molecular Engineering of Functional Materials, Institute of Chemical Sciences and Engineering, School of Basic Sciences; Ecole Polytechnique Fédérale de Lausanne Valais (EPFL-Valais); Rue de L'industrie 17 Sion CH- 1951 Switzerland
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19
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Liao W, Zhao D, Yu Y, Shrestha N, Ghimire K, Grice CR, Wang C, Xiao Y, Cimaroli AJ, Ellingson RJ, Podraza NJ, Zhu K, Xiong RG, Yan Y. Fabrication of Efficient Low-Bandgap Perovskite Solar Cells by Combining Formamidinium Tin Iodide with Methylammonium Lead Iodide. J Am Chem Soc 2016; 138:12360-3. [DOI: 10.1021/jacs.6b08337] [Citation(s) in RCA: 306] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Weiqiang Liao
- Department
of Physics and Astronomy and Wright Center for Photovoltaics Innovation
and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
- Ordered
Matter Science Research Center, Southeast University, Nanjing 211189, China
| | - Dewei Zhao
- Department
of Physics and Astronomy and Wright Center for Photovoltaics Innovation
and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Yue Yu
- Department
of Physics and Astronomy and Wright Center for Photovoltaics Innovation
and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Niraj Shrestha
- Department
of Physics and Astronomy and Wright Center for Photovoltaics Innovation
and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Kiran Ghimire
- Department
of Physics and Astronomy and Wright Center for Photovoltaics Innovation
and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Corey R. Grice
- Department
of Physics and Astronomy and Wright Center for Photovoltaics Innovation
and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Changlei Wang
- Department
of Physics and Astronomy and Wright Center for Photovoltaics Innovation
and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
- Key
Laboratory of Artificial Micro/Nano Structures of Ministry of Education,
School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Yuqing Xiao
- Key
Laboratory of Artificial Micro/Nano Structures of Ministry of Education,
School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Alexander J. Cimaroli
- Department
of Physics and Astronomy and Wright Center for Photovoltaics Innovation
and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Randy J. Ellingson
- Department
of Physics and Astronomy and Wright Center for Photovoltaics Innovation
and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Nikolas J. Podraza
- Department
of Physics and Astronomy and Wright Center for Photovoltaics Innovation
and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Kai Zhu
- Chemistry
and Nanoscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Ren-Gen Xiong
- Ordered
Matter Science Research Center, Southeast University, Nanjing 211189, China
| | - Yanfa Yan
- Department
of Physics and Astronomy and Wright Center for Photovoltaics Innovation
and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
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20
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Phillips AB, Song Z, DeWitt JL, Stone JM, Krantz PW, Royston JM, Zeller RM, Mapes MR, Roland PJ, Dorogi MD, Zafar S, Faykosh GT, Ellingson RJ, Heben MJ. High speed, intermediate resolution, large area laser beam induced current imaging and laser scribing system for photovoltaic devices and modules. Rev Sci Instrum 2016; 87:093708. [PMID: 27782537 DOI: 10.1063/1.4962940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We have developed a laser beam induced current imaging tool for photovoltaic devices and modules that utilizes diode pumped Q-switched lasers. Power densities on the order of one sun (100 mW/cm2) can be produced in a ∼40 μm spot size by operating the lasers at low diode current and high repetition rate. Using galvanostatically controlled mirrors in an overhead configuration and high speed data acquisition, large areas can be scanned in short times. As the beam is rastered, focus is maintained on a flat plane with an electronically controlled lens that is positioned in a coordinated fashion with the movements of the mirrors. The system can also be used in a scribing mode by increasing the diode current and decreasing the repetition rate. In either mode, the instrument can accommodate samples ranging in size from laboratory scale (few cm2) to full modules (1 m2). Customized LabVIEW programs were developed to control the components and acquire, display, and manipulate the data in imaging mode.
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Affiliation(s)
- Adam B Phillips
- Wright Center for Photovoltaic Innovation and Commercialization (PVIC), Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
| | - Zhaoning Song
- Wright Center for Photovoltaic Innovation and Commercialization (PVIC), Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
| | - Jonathan L DeWitt
- Wright Center for Photovoltaic Innovation and Commercialization (PVIC), Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
| | - Jon M Stone
- Wright Center for Photovoltaic Innovation and Commercialization (PVIC), Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
| | - Patrick W Krantz
- Wright Center for Photovoltaic Innovation and Commercialization (PVIC), Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
| | - John M Royston
- Wright Center for Photovoltaic Innovation and Commercialization (PVIC), Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
| | - Ryan M Zeller
- Wright Center for Photovoltaic Innovation and Commercialization (PVIC), Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
| | - Meghan R Mapes
- Wright Center for Photovoltaic Innovation and Commercialization (PVIC), Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
| | - Paul J Roland
- Wright Center for Photovoltaic Innovation and Commercialization (PVIC), Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
| | - Mark D Dorogi
- Willard and Kelsey Solar Group, Perrysburg, Ohio 43551, USA
| | - Syed Zafar
- Willard and Kelsey Solar Group, Perrysburg, Ohio 43551, USA
| | - Gary T Faykosh
- Willard and Kelsey Solar Group, Perrysburg, Ohio 43551, USA
| | - Randy J Ellingson
- Wright Center for Photovoltaic Innovation and Commercialization (PVIC), Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
| | - Michael J Heben
- Wright Center for Photovoltaic Innovation and Commercialization (PVIC), Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
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21
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Bastola E, Bhandari KP, Matthews AJ, Shrestha N, Ellingson RJ. Elemental anion thermal injection synthesis of nanocrystalline marcasite iron dichalcogenide FeSe2 and FeTe2. RSC Adv 2016. [DOI: 10.1039/c6ra06351a] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We report a hot-injection colloidal method for the synthesis of nanocrystalline (NC) iron diselenide (FeSe2), and iron ditelluride (FeTe2) derived from iron(ii) bromide as the iron (Fe) precursor.
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Affiliation(s)
- Ebin Bastola
- Wright Center for Photovoltaics Innovation and Commercialization
- School for Solar and Advanced Renewable Energy
- Department of Physics and Astronomy
- The University of Toledo
- Toledo
| | - Khagendra P. Bhandari
- Wright Center for Photovoltaics Innovation and Commercialization
- School for Solar and Advanced Renewable Energy
- Department of Physics and Astronomy
- The University of Toledo
- Toledo
| | - Anthony J. Matthews
- Wright Center for Photovoltaics Innovation and Commercialization
- School for Solar and Advanced Renewable Energy
- Department of Physics and Astronomy
- The University of Toledo
- Toledo
| | - Niraj Shrestha
- Wright Center for Photovoltaics Innovation and Commercialization
- School for Solar and Advanced Renewable Energy
- Department of Physics and Astronomy
- The University of Toledo
- Toledo
| | - Randy J. Ellingson
- Wright Center for Photovoltaics Innovation and Commercialization
- School for Solar and Advanced Renewable Energy
- Department of Physics and Astronomy
- The University of Toledo
- Toledo
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22
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Gao J, Perkins CL, Luther JM, Hanna MC, Chen HY, Semonin OE, Nozik AJ, Ellingson RJ, Beard MC. n-Type transition metal oxide as a hole extraction layer in PbS quantum dot solar cells. Nano Lett 2011; 11:3263-6. [PMID: 21688813 DOI: 10.1021/nl2015729] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The n-type transition metal oxides (TMO) consisting of molybdenum oxide (MoO(x)) and vanadium oxide (V(2)O(x)) are used as an efficient hole extraction layer (HEL) in heterojunction ZnO/PbS quantum dot solar cells (QDSC). A 4.4% NREL-certified device based on the MoO(x) HEL is reported with Al as the back contact material, representing a more than 65% efficiency improvement compared with the case of Au contacting the PbS quantum dot (QD) layer directly. We find the acting mechanism of the hole extraction layer to be a dipole formed at the MoO(x) and PbS interface enhancing band bending to allow efficient hole extraction from the valence band of the PbS layer by MoO(x). The carrier transport to the metal anode is likely enhanced through shallow gap states in the MoO(x) layer.
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Affiliation(s)
- Jianbo Gao
- National Renewable Energy Laboratory, Golden, Colorado, United States.
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23
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Gao J, Luther JM, Semonin OE, Ellingson RJ, Nozik AJ, Beard MC. Quantum dot size dependent J-V characteristics in heterojunction ZnO/PbS quantum dot solar cells. Nano Lett 2011; 11:1002-8. [PMID: 21291196 DOI: 10.1021/nl103814g] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The current-voltage (J-V) characteristics of ZnO/PbS quantum dot (QD) solar cells show a QD size-dependent behavior resulting from a Schottky junction that forms at the back metal electrode opposing the desirable diode formed between the ZnO and PbS QD layers. We study a QD size-dependent roll-over effect that refers to the saturation of photocurrent in forward bias and crossover effect which occurs when the light and dark J-V curves intersect. We model the J-V characteristics with a main diode formed between the n-type ZnO nanocrystal (NC) layer and p-type PbS QD layer in series with a leaky Schottky-diode formed between PbS QD layer and metal contact. We show how the characteristics of the two diodes depend on QD size, metal work function, and PbS QD layer thickness, and we discuss how the presence of the back diode complicates finding an optimal layer thickness. Finally, we present Kelvin probe measurements to determine the Fermi level of the QD layers and discuss band alignment, Fermi-level pinning, and the V(oc) within these devices.
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Affiliation(s)
- Jianbo Gao
- Chemical and Material Sciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
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24
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Beard MC, Midgett AG, Law M, Semonin OE, Ellingson RJ, Nozik AJ. Variations in the quantum efficiency of multiple exciton generation for a series of chemically treated PbSe nanocrystal films. Nano Lett 2009; 9:836-845. [PMID: 19170560 DOI: 10.1021/nl803600v] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We study multiple exciton generation (MEG) in two series of chemically treated PbSe nanocrystal (NC) films. We find that the average number of excitons produced per absorbed photon varies between 1.0 and 2.4 (+/-0.2) at a photon energy of approximately 4E(g) for films consisting of 3.7 nm NCs and between 1.1 and 1.6 (+/-0.1) at hnu approximately 5E(g) for films consisting of 7.4 nm NCs. The variations in MEG depend upon the chemical treatment used to electronically couple the NCs in each film. The single and multiexciton lifetimes also change with the chemical treatment: biexciton lifetimes increase with stronger inter-NC electronic coupling and exciton delocalization, while single exciton lifetimes decrease after most treatments relative to the same NCs in solution. Single exciton lifetimes are particularly affected by surface treatments that dope the films n-type, which we tentatively attribute to an Auger recombination process between a single exciton and an electron produced by ionization of the dopant donor. These results imply that a better understanding of the effects of surface chemistry on film doping, NC carrier dynamics, and inter-NC interactions is necessary to build solar energy conversion devices that can harvest the multiple carriers produced by MEG. Our results show that the MEG efficiency is very sensitive to the condition of the NC surface and suggest that the wide range of MEG efficiencies reported in the recent literature may be a result of uncontrolled differences in NC surface chemistry.
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Affiliation(s)
- Matthew C Beard
- Basic Sciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
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25
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Luther JM, Law M, Beard MC, Song Q, Reese MO, Ellingson RJ, Nozik AJ. Schottky solar cells based on colloidal nanocrystal films. Nano Lett 2008; 8:3488-92. [PMID: 18729414 DOI: 10.1021/nl802476m] [Citation(s) in RCA: 432] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We describe here a simple, all-inorganic metal/NC/metal sandwich photovoltaic (PV) cell that produces an exceptionally large short-circuit photocurrent (>21 mA cm(-2)) by way of a Schottky junction at the negative electrode. The PV cell consists of a PbSe NC film, deposited via layer-by-layer (LbL) dip coating that yields an EQE of 55-65% in the visible and up to 25% in the infrared region of the solar spectrum, with a spectrally corrected AM1.5G power conversion efficiency of 2.1%. This NC device produces one of the largest short-circuit currents of any nanostructured solar cell, without the need for sintering, superlattice order or separate phases for electron and hole transport.
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Affiliation(s)
- Joseph M Luther
- National Renewable Energy Laboratory, Golden, Colorado 80401, USA
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26
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Beard MC, Knutsen KP, Yu P, Luther JM, Song Q, Metzger WK, Ellingson RJ, Nozik AJ. Multiple exciton generation in colloidal silicon nanocrystals. Nano Lett 2007; 7:2506-12. [PMID: 17645368 DOI: 10.1021/nl071486l] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Multiple exciton generation (MEG) is a process whereby multiple electron-hole pairs, or excitons, are produced upon absorption of a single photon in semiconductor nanocrystals (NCs) and represents a promising route to increased solar conversion efficiencies in single-junction photovoltaic cells. We report for the first time MEG yields in colloidal Si NCs using ultrafast transient absorption spectroscopy. We find the threshold photon energy for MEG in 9.5 nm diameter Si NCs (effective band gap identical with Eg = 1.20 eV) to be 2.4 +/- 0.1Eg and find an exciton-production quantum yield of 2.6 +/- 0.2 excitons per absorbed photon at 3.4Eg. While MEG has been previously reported in direct-gap semiconductor NCs of PbSe, PbS, PbTe, CdSe, and InAs, this represents the first report of MEG within indirect-gap semiconductor NCs. Furthermore, MEG is found in relatively large Si NCs (diameter equal to about twice the Bohr radius) such that the confinement energy is not large enough to produce a large blue-shift of the band gap (only 80 meV), but the Coulomb interaction is sufficiently enhanced to produce efficient MEG. Our findings are of particular importance because Si dominates the photovoltaic solar cell industry, presents no problems regarding abundance and accessibility within the Earth's crust, and poses no significant environmental problems regarding toxicity.
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Affiliation(s)
- Matthew C Beard
- National Renewable Energy Laboratory, Golden, Colorado 80401, USA. matt_
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27
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Yu P, Beard MC, Ellingson RJ, Ferrere S, Curtis C, Drexler J, Luiszer F, Nozik AJ. Absorption cross-section and related optical properties of colloidal InAs quantum dots. J Phys Chem B 2007; 109:7084-7. [PMID: 16851806 DOI: 10.1021/jp046127i] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the absorption cross-section of colloidal InAs quantum dots of mean radii from 1.6 to 3.45 nm. We find excellent agreement between the measured results and calculated values based on a model of small-particle light absorption. The absorption cross-section per dot is 6.2 x 10(-16)R(3) cm(2) at 2.76 eV and 3.15 x 10(-16)R(1.28) cm(2) at the first-exciton absorption peak, with the dot radius R in nm. We find that the per-quantum-dot particle oscillator strength of the first-exciton transition is constant for all sizes studied. The radiative lifetime of the first exciton calculated from the oscillator strength increases with dot size and ranges from 4 ns for the smallest dots to 14 ns for the largest ones.
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Affiliation(s)
- Pingrong Yu
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
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28
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Blackburn JL, Selmarten DC, Ellingson RJ, Jones M, Micic O, Nozik AJ. Electron and hole transfer from indium phosphide quantum dots. J Phys Chem B 2007; 109:2625-31. [PMID: 16851267 DOI: 10.1021/jp046781y] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electron- and hole-transfer reactions are studied in colloidal InP quantum dots (QDs). Photoluminescence quenching and time-resolved transient absorption (TA) measurements are utilized to examine hole transfer from photoexcited InP QDs to the hole acceptor N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) and electron transfer to nanocrystalline titanium dioxide (TiO2) films. Core-confined holes are effectively quenched by TMPD, resulting in a new approximately 4-ps component in the TA decay. It is found that electron transfer to TiO2 is primarily mediated through surface-localized states on the InP QDs.
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Affiliation(s)
- J L Blackburn
- National Renewable Energy Laboratory, Golden, Colorado 80401, USA
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29
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Luther JM, Beard MC, Song Q, Law M, Ellingson RJ, Nozik AJ. Multiple exciton generation in films of electronically coupled PbSe quantum dots. Nano Lett 2007; 7:1779-84. [PMID: 17530913 DOI: 10.1021/nl0708617] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We study multiple exciton generation (MEG) in electronically coupled films of PbSe quantum dots (QDs) employing ultrafast time-resolved transient absorption spectroscopy. We demonstrate that the MEG efficiency in PbSe does not decrease when the QDs are treated with hydrazine, which has been shown to greatly enhance carrier transport in PbSe QD films by decreasing the interdot distance. The quantum yield is measured and compared to previously reported values for electronically isolated QDs suspended in organic solvents at approximately 4 and 4.5 times the effective band gap. A slightly modified analysis is applied to extract the MEG efficiency and the absorption cross section of each sample at the pump wavelength. We compare the absorption cross sections of our samples to that of bulk PbSe. We find that both the biexciton lifetime and the absorption cross section increase in films relative to isolated QDs in solution.
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Affiliation(s)
- Joseph M Luther
- Chemical and Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
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30
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Jones M, Metzger WK, McDonald TJ, Engtrakul C, Ellingson RJ, Rumbles G, Heben MJ. Extrinsic and intrinsic effects on the excited-state kinetics of single-walled carbon nanotubes. Nano Lett 2007; 7:300-6. [PMID: 17243749 DOI: 10.1021/nl0622808] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We characterized the photoluminescence (PL) decay of 15 different, solubilized single-walled carbon nanotubes with tube diameters that ranged from 0.7 to 1.1 nm using time-correlated single photon counting. Each nanotube species was excited resonantly at the second excited state, E2, and PL was detected at the lowest energy exciton emission, E1. In a 10 ns window, the PL decays were described well by a biexponential fitting function with two characteristic time constants, suggesting that at least two kinetically distinct relaxation processes were observed. The dominant decay component increased from 60 to 200 ps with increasing tube diameter, while the lesser component, which contributed up to 8% of the total decay, increased from 200 ps to 4.8 ns. The observation of the second, longer decay time component is examined in terms of two possible models: an extrinsic behavior that implicates sample inhomogeneity and an intrinsic process associated with interconversion between kinetically distinct bright and dark exciton states. A common conclusion from both models is that nonradiative decay controls the PL decay by a process that is diameter dependent.
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Affiliation(s)
- Marcus Jones
- Chemical and Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401-3393, USA
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31
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Ai X, Xu Q, Jones M, Song Q, Ding SY, Ellingson RJ, Himmel M, Rumbles G. Photophysics of (CdSe)ZnS colloidal quantum dots in an aqueous environment stabilized with amino acids and genetically-modified proteins. Photochem Photobiol Sci 2007; 6:1027-33. [PMID: 17721603 DOI: 10.1039/b706471c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using a combination of two amino acids, histidine and N-acetyl-cysteine, to replace the original organic capping groups of (CdSe)ZnS quantum dots, water-soluble and highly luminescent (CdSe)ZnS quantum dots have been successfully prepared at pH 8. Characterization by steady-state and time-resolved photoluminescence spectroscopy, and transient absorption spectroscopy, demonstrate that the electronic properties of these quantum dots exceed those of the original as-synthesized samples dissolved in a more-conventional organic solvent. Furthermore, these amino acid-stabilized quantum dots have been assembled onto a cellulose substrate via cellulose binding proteins that specifically bind to cellulose and was genetically engineered to harbor dual hexahistidine tags at the N- and C-termini to confer binding with the zinc(II) on the quantum dot surface. The spectroscopic measurements show that the protein-bound quantum dots continue to retain their desirable electronic properties when bound on the substrate. Meanwhile, the specific and very selective binding properties of the proteins have remained effective.
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Affiliation(s)
- Xin Ai
- National Renewable Energy Laboratory, 1617 Cole Blvd, Golden, CO 80401-3393, USA
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32
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Ai X, Beard MC, Knutsen KP, Shaheen SE, Rumbles G, Ellingson RJ. Photoinduced Charge Carrier Generation in a Poly(3-hexylthiophene) and Methanofullerene Bulk Heterojunction Investigated by Time-Resolved Terahertz Spectroscopy. J Phys Chem B 2006; 110:25462-71. [PMID: 17165994 DOI: 10.1021/jp065212i] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report on the ultrafast photoinduced charge separation processes in varying compositions of poly(3-hexylthiophene) (P3HT) blended with the electron acceptor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Through the use of time-resolved terahertz spectroscopy, the time- and frequency-dependent complex photoconductivity is measured for samples with PCBM weight fractions (WPCBM) of 0, 0.2, 0.5, and 0.8. By analysis of the frequency-dependent complex conductivity, both the charge carrier yield and the average charge carrier mobility have been determined analytically and indicate a short (<0.2 nm) carrier mean free path and a suppressed long-range transport that is characteristic of carrier localization. Studies on pure films of P3HT demonstrate that charge carrier generation is an intrinsic feature of the polymer that occurs on the time scale of the excitation light, and this is attributed to the dissociation of bound polaron pairs that reside on adjacent polymer chains due to interchain charge transfer. Both interchain and interfacial charge transfer contribute to the measured photoconductivity from the blended samples; interfacial charge transfer increases as a function of increasing PCBM. The addition of PCBM to the polymer films surprisingly does not dramatically increase the production of charge carriers within the first 2 ps. However, charge carriers in the 0.2 and 0.5 blended films survive to much longer times than those in the P3HT and 0.8 films.
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Affiliation(s)
- Xin Ai
- National Renewable Energy Laboratory, Golden, Colorado 80401, USA
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33
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Murphy JE, Beard MC, Norman AG, Ahrenkiel SP, Johnson JC, Yu P, Mićić OI, Ellingson RJ, Nozik AJ. PbTe Colloidal Nanocrystals: Synthesis, Characterization, and Multiple Exciton Generation. J Am Chem Soc 2006; 128:3241-7. [PMID: 16522105 DOI: 10.1021/ja0574973] [Citation(s) in RCA: 596] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report an alternative synthesis and the first optical characterization of colloidal PbTe nanocrystals (NCs). We have synthesized spherical PbTe NCs having a size distribution as low as 7%, ranging in diameter from 2.6 to 8.3 nm, with first exciton transitions tuned from 1009 to 2054 nm. The syntheses of colloidal cubic-like PbSe and PbTe NCs using a PbO "one-pot" approach are also reported. The photoluminescence quantum yield of PbTe spherical NCs was measured to be as high as 52 +/- 2%. We also report the first known observation of efficient multiple exciton generation (MEG) from single photons absorbed in PbTe NCs. Finally, we report calculated longitudinal and transverse Bohr radii for PbS, PbSe, and PbTe NCs to account for electronic band anisotropy. This is followed by a comparison of the differences in the electronic band structure and optical properties of these lead salts.
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Affiliation(s)
- James E Murphy
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
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34
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Ellingson RJ, Beard MC, Johnson JC, Yu P, Micic OI, Nozik AJ, Shabaev A, Efros AL. Highly efficient multiple exciton generation in colloidal PbSe and PbS quantum dots. Nano Lett 2005; 5:865-71. [PMID: 15884885 DOI: 10.1021/nl0502672] [Citation(s) in RCA: 675] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We report ultra-efficient multiple exciton generation (MEG) for single photon absorption in colloidal PbSe and PbS quantum dots (QDs). We employ transient absorption spectroscopy and present measurement data acquired for both intraband as well as interband probe energies. Quantum yields of 300% indicate the creation, on average, of three excitons per absorbed photon for PbSe QDs at photon energies that are four times the QD energy gap. Results indicate that the threshold photon energy for MEG in QDs is twice the lowest exciton absorption energy. We find that the biexciton effect, which shifts the transition energy for absorption of a second photon, influences the early time transient absorption data and may contribute to a modulation observed when probing near the lowest interband transition. We present experimental and theoretical values of the size-dependent interband transition energies for PbSe QDs. We present experimental and theoretical values of the size-dependent interband transition energies for PbSe QDs, and we also introduce a new model for MEG based on the coherent superposition of multiple excitonic states.
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Affiliation(s)
- Randy J Ellingson
- Center for Basic Sciences, National Renewable Energy Laborarory, Golden, Colorado 80401, USA.
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35
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Affiliation(s)
- Marcus Jones
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401-3393
| | - Jovan Nedeljkovic
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401-3393
| | - Randy J. Ellingson
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401-3393
| | - Arthur J. Nozik
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401-3393
| | - Garry Rumbles
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401-3393
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36
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Blackburn JL, Ellingson RJ, Mićić OI, Nozik AJ. Electron Relaxation in Colloidal InP Quantum Dots with Photogenerated Excitons or Chemically Injected Electrons. J Phys Chem B 2002. [DOI: 10.1021/jp026746w] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jeff L. Blackburn
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado, 80401
| | - Randy J. Ellingson
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado, 80401
| | - Olga I. Mićić
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado, 80401
| | - Arthur J. Nozik
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado, 80401
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Ellingson RJ, Blackburn JL, Yu P, Rumbles G, Mićić OI, Nozik AJ. Excitation Energy Dependent Efficiency of Charge Carrier Relaxation and Photoluminescence in Colloidal InP Quantum Dots. J Phys Chem B 2002. [DOI: 10.1021/jp025666p] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Randy J. Ellingson
- Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Jeff L. Blackburn
- Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Pingrong Yu
- Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Garry Rumbles
- Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Olga I. Mićić
- Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Arthur J. Nozik
- Center for Basic Science, National Renewable Energy Laboratory, Golden, Colorado 80401
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Rumbles G, Selmarten DC, Ellingson RJ, Blackburn JL, Yu P, Smith BB, Mićić OI, Nozik AJ. Anomalies in the linear absorption, transient absorption, photoluminescence and photoluminescence excitation spectroscopies of colloidal InP quantum dots. J Photochem Photobiol A Chem 2001. [DOI: 10.1016/s1010-6030(01)00513-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ellingson RJ, Asbury JB, Ferrere S, Ghosh HN, Sprague JR, Lian T, Nozik AJ. Sub-picosecond Injection of Electrons from Excited [Ru(2,2′-bipy-4,4′-dicarboxy)2(SCN)2] into TiO2 Using Transient Mid-Infrared Spectroscopy*. ACTA ACUST UNITED AC 1999. [DOI: 10.1524/zpch.1999.212.part_1.077] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Randy J. Ellingson
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado, 80401, USA
| | - John B. Asbury
- Department of Chemistry, Emory University, Atlanta, Georgia, 30322, USA
| | - Sue Ferrere
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado, 80401, USA
| | - Hirendra N. Ghosh
- Department of Chemistry, Emory University, Atlanta, Georgia, 30322, USA
| | - Julian R. Sprague
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado, 80401, USA
| | - Tianquan Lian
- Department of Chemistry, Emory University, Atlanta, Georgia, 30322, USA
| | - Arthur J. Nozik
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado, 80401, USA
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Asbury JB, Ellingson RJ, Ghosh HN, Ferrere S, Nozik AJ, Lian T. Femtosecond IR Study of Excited-State Relaxation and Electron-Injection Dynamics of Ru(dcbpy)2(NCS)2 in Solution and on Nanocrystalline TiO2 and Al2O3 Thin Films. J Phys Chem B 1999. [DOI: 10.1021/jp983915x] [Citation(s) in RCA: 325] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- John B. Asbury
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, and National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Randy J. Ellingson
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, and National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Hirendra N. Ghosh
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, and National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Suzanne Ferrere
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, and National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Arthur J. Nozik
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, and National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Tianquan Lian
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, and National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
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Ellingson RJ, Asbury JB, Ferrere S, Ghosh HN, Sprague JR, Lian T, Nozik AJ. Dynamics of Electron Injection in Nanocrystalline Titanium Dioxide Films Sensitized with [Ru(4,4‘-dicarboxy-2,2‘-bipyridine)2(NCS)2] by Infrared Transient Absorption. J Phys Chem B 1998. [DOI: 10.1021/jp982310y] [Citation(s) in RCA: 263] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Randy J. Ellingson
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado, 80401, and Department of Chemistry, Emory University, Atlanta, Georgia, 30322
| | - John B. Asbury
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado, 80401, and Department of Chemistry, Emory University, Atlanta, Georgia, 30322
| | - Sue Ferrere
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado, 80401, and Department of Chemistry, Emory University, Atlanta, Georgia, 30322
| | - Hirendra N. Ghosh
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado, 80401, and Department of Chemistry, Emory University, Atlanta, Georgia, 30322
| | - Julian R. Sprague
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado, 80401, and Department of Chemistry, Emory University, Atlanta, Georgia, 30322
| | - Tianquan Lian
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado, 80401, and Department of Chemistry, Emory University, Atlanta, Georgia, 30322
| | - Arthur J. Nozik
- Center for Basic Sciences, National Renewable Energy Laboratory, Golden, Colorado, 80401, and Department of Chemistry, Emory University, Atlanta, Georgia, 30322
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Enoch MA, Rohrbaugh JW, Davis EZ, Harris CR, Ellingson RJ, Andreason P, Moore V, Varner JL, Brown GL, Eckardt MJ. Relationship of genetically transmitted alpha EEG traits to anxiety disorders and alcoholism. Am J Med Genet 1995; 60:400-8. [PMID: 8546153 DOI: 10.1002/ajmg.1320600510] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We tested the hypothesis that a heritable EEG trait, the low voltage alpha (LV), is associated with psychiatric disorders. Modest to moderate evidence for genetic linkage of both panic disorder and the low voltage alpha trait to the same region of chromosome 20q has recently been reported, raising the issue of whether there is a phenotypic correlation between these traits. A total of 124 subjects including 50 unrelated index subjects and 74 relatives were studied. Alpha EEG power was measured and EEG phenotypes were impressionistically classified. Subjects were psychiatrically interviewed using the SADS-L and blind-rated by RDC criteria. Alcoholics were four times more likely to be LV (including so-called borderline low voltage alpha) than were nonalcoholic, nonanxious subjects. Alcoholics with anxiety disorder are 10 times more likely to be LV. However, alcoholics without anxiety disorder were similar to nonalcoholics in alpha power. An anxiety disorder (panic disorder, phobia, or generalized anxiety) was found in 14/17 LV subjects as compared to 34/101 of the rest of the sample (P < 0.01). Support for these observations was found in the unrelated index subjects in whom no traits would be shared by familial clustering. Lower alpha power in anxiety disorders was not state-dependent, as indicated by the Spielberger Anxiety Scale. Familial covariance of alpha power was 0.25 (P < 0.01). These findings indicate there may be a shared factor underlying the transmissible low voltage alpha EEG variant and vulnerability to anxiety disorders with associated alcoholism. This factor is apparently not rare, because LV was found in approximately 10% of unrelated index subjects and 5% of subjects free of alcoholism and anxiety disorders.
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Affiliation(s)
- M A Enoch
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, USA
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Ellingson RJ, Wszolek ZK, Kendall JD, Donovan JP, Schafer DF. Brainstem auditory evoked potentials in liver transplant candidates. Nebr Med J 1995; 80:167-70. [PMID: 7651553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BAEPs were recorded on 18 patients before, and/or after liver transplantation. Clinical assessment included 5 standardized scales. Data were divided by stringent criteria into 2 groups: clinical hepatic encephalopathy present (HE) or absent (nonHE). Dependent variables were BAEP configuration and I-V, I-III and III-V IPLs. The following comparisons were made: all patients vs. controls; HE vs. controls; nonHE vs. controls; HE vs. nonHE. BAEP configuration changes were not significantly associated with HE. I-V and III-V IPLs were prolonged for all patients, nonHE patients, and HE patients vs. controls; I-III IPL differences were not significant. There were no correlations between BAEP variables and EEG grade or grades on any single clinical scale. The results suggest that BAEP IPLs (especially the I-V IPL) are a sensitive, although not specific, measure of HE and may be sensitive enough to detect incipient HE.
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Affiliation(s)
- R J Ellingson
- University of Nebraska Medical Center, Omaha 68198-2045, USA
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Abstract
We demonstrate a Ti:sapphire-pumped intracavity-doubled optical parametric oscillator (OPO) that generates a total of up to 240 mW of sub-100-fs pulses tunable in the visible. The OPO consists of a 1.5-mm-thick KTiPO(4) (KTP) crystal configured in a ring cavity that is synchronously pumped by a self-mode-locked Ti:sapphire laser operating at an 81-MHz repetition rate and 2.1-W average power, producing 115-fs pulses at lambda = 790 nm. Intracavity doubling of the OPO is accomplished by inserting a 47-microm-thick beta-BaB(2)O(4) crystal into an additional focus in the OPO cavity. We demonstrate continuous tuning of the second-harmonic output from 580 to 657 nm. The potential tuning range of this intracavity-doubled KTP OPO is approximately 500 to 800 nm.
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Pelouch WS, Ellingson RJ, Powers PE, Tang CL, Szmyd DM, Nozik AJ. Comparison of hot-carrier relaxation in quantum wells and bulk GaAs at high carrier densities. Phys Rev B Condens Matter 1992; 45:1450-1453. [PMID: 10001629 DOI: 10.1103/physrevb.45.1450] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Tsao CY, Ellingson RJ, Wright FS. Recovery of cognition from persistent vegetative state in a child with normal somatosensory evoked potentials. Clin Electroencephalogr 1991; 22:141-3. [PMID: 1879052 DOI: 10.1177/155005949102200304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The absence of bilateral early cortical SEPs in a PVS due to nontraumatic coma is usually associated with failure to recover cognition or awareness, although rarely patients with bilaterally absent cortical SEPs in posttraumatic PVS may regain cognition. On the other hand, normal cortical SEPs in nontraumatic coma may be related to favorable outcomes as shown in this patient and other reports. Our patient is unique in that he had had serial normal SEPs, was in a PVS for 7 1/2 months, and recovered cognition, but not without cost in terms of damage to intellectual capability. Further long-term clinical follow-up studies to correlate clinical outcome with serial SEP data may be indicated.
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Affiliation(s)
- C Y Tsao
- Department of Pediatrics, Children's Hospital, Ohio State University, Columbus 43205
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Wszolek ZK, Aksamit AJ, Ellingson RJ, Sharbrough FW, Westmoreland BF, Pfeiffer RF, Steg RE, de Groen PC. Epileptiform electroencephalographic abnormalities in liver transplant recipients. Ann Neurol 1991; 30:37-41. [PMID: 1929227 DOI: 10.1002/ana.410300108] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We retrospectively studied patients who had undergone orthotopic liver transplantation and who also had electroencephalography to determine whether epileptiform changes were associated with a poor neurological outcome. Study groups were 36 patients who died after transplantation (141 electroencephalograms) and underwent neuropathological examination, 11 who died (18 electroencephalograms) but did not have autopsy, and a third group of 34 (62 electroencephalograms) who remained alive. Epileptiform activity was seen in electroencephalograms of 14 of the patients who died (11 from the autopsy group) and in 2 of those who remained alive. All had multiple epileptiform abnormalities and clinical or subclinical seizures. The incidence of epileptiform activity after orthotopic liver transplantation was fivefold higher in the nonsurvivors. Serious cerebral structural changes were found in 10 of the 11 patients who underwent autopsy. Epileptiform activity in the electroencephalograms of patients who had undergone orthotopic liver transplantation indicates a poor prognosis. It should alert the clinician to investigate further for potentially treatable causes.
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Affiliation(s)
- Z K Wszolek
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
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Rohrbaugh JW, Varner JL, Paige SR, Eckardt MJ, Ellingson RJ. Event-related perturbations in an electrophysiological measure of auditory sensitivity: effects of probability, intensity and repeated sessions. Int J Psychophysiol 1990; 10:17-32. [PMID: 2269644 DOI: 10.1016/0167-8760(90)90041-b] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
It is often held that novel or salient stimuli are followed by a brief period of orienting or alerting during which sensory processes are facilitated. Evidence for such a period of facilitation was sought in a paradigm in which evoked responses to weak auditory probe stimuli were examined when given in the presence of salient foreground stimuli, which were varied in probability and intensity, and which were given in two replicate sessions. The background probe stimuli consisted of a continuous train of auditory pip stimuli delivered at a rate of 40 pips per second. Under such conditions of repetitive stimulation a steady-state rhythm (SSR), which is believed to reflect summated early and middle latency evoked responses, is established in the EEG at a corresponding frequency of 40 Hz. The 40 Hz SSR was extracted using a digital averaging and filtering technique and examined continuously for changes in amplitude and latency. The rhythm showed a brief episode during which the latencies of response were decreased. The reduction in latency was greatest at 186 ms after the foreground stimulus, at which time the latencies of individual peaks in the rhythm were reduced by about 3.5 ms. The magnitude of the latency reduction response was larger for intense and for rare stimuli, and showed long-term decrement during the second session. Event-related potential and heart rate responses to the foreground stimulus were also affected by probability, intensity and session, but not in the same pattern. It was hypothesized that the latency shift in the 40 Hz SSR reflects a brief period of sensitization during alerting or orienting responses.
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Affiliation(s)
- J W Rohrbaugh
- Laboratory of Clinical Studies, National Institute on Alcohol Abuse and Alcoholism, DICBR, Bethesda, MD 20892
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Rohrbaugh JW, Varner JL, Paige SR, Eckardt MJ, Ellingson RJ. Auditory and visual event-related perturbations in the 40 Hz auditory steady-state response. Electroencephalogr Clin Neurophysiol 1990; 76:148-64. [PMID: 1697243 DOI: 10.1016/0013-4694(90)90213-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effects of salient auditory and visual 'foreground' stimuli on responses to 'background' probe stimuli were investigated. The foreground stimuli were given at long and aperiodic intervals and required a discriminative judgment. Simultaneously, evoked potentials were obtained in response to background probe auditory stimuli presented in a continuous train at about 40/sec. The 40 Hz steady-state rhythm (SSR) evoked under such conditions was extracted using digital averaging and filtering techniques and examined continuously for evidence of change in latency or amplitude during the period surrounding the foreground stimulus. Within the first 200-300 msec after the onset of an acoustic foreground stimulus the latencies of individual peaks in the rhythm were momentarily reduced by a mean of 5.5 msec. A shift in the 40 Hz rhythm was also seen following visual foreground stimuli, although the shift was about one-third that following acoustic stimuli. A latency shift of comparable magnitude was not produced by deliberate manipulation of intensity or signal-to-noise ratio of the stimuli used to evoke the rhythm. The latency shift response is discussed in terms of a transient period of sensory facilitation during orienting or alerting associated with the foreground stimuli.
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Affiliation(s)
- J W Rohrbaugh
- Laboratory of Clinical Studies, National Institute on Alcohol Abuse and Alcoholism, DICBR, Bethesda, MD 20892
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