1
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Hensling FVE, Dahliah D, Smeaton MA, Shrestha B, Show V, Parzyck CT, Hennighausen C, Kotsonis GN, Rignanese GM, Barone MR, Subedi I, Disa AS, Shen KM, Faeth BD, Bollinger AT, Božović I, Podraza NJ, Kourkoutis LF, Hautier G, Schlom DG. Is Ba 3In 2O 6a high- Tcsuperconductor? J Phys Condens Matter 2024; 36:315602. [PMID: 38657622 DOI: 10.1088/1361-648x/ad42f3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/24/2024] [Indexed: 04/26/2024]
Abstract
It has been suggested that Ba3In2O6might be a high-Tcsuperconductor. Experimental investigation of the properties of Ba3In2O6was long inhibited by its instability in air. Recently epitaxial Ba3In2O6with a protective capping layer was demonstrated, which finally allows its electronic characterization. The optical bandgap of Ba3In2O6is determined to be 2.99 eV in-the (001) plane and 2.83 eV along thec-axis direction by spectroscopic ellipsometry. First-principles calculations were carried out, yielding a result in good agreement with the experimental value. Various dopants were explored to induce (super-)conductivity in this otherwise insulating material. NeitherA- norB-site doping proved successful. The underlying reason is predominately the formation of oxygen interstitials as revealed by scanning transmission electron microscopy and first-principles calculations. Additional efforts to induce superconductivity were investigated, including surface alkali doping, optical pumping, and hydrogen reduction. To probe liquid-ion gating, Ba3In2O6was successfully grown epitaxially on an epitaxial SrRuO3bottom electrode. So far none of these efforts induced superconductivity in Ba3In2O6,leaving the answer to the initial question of whether Ba3In2O6is a high-Tcsuperconductor to be 'no' thus far.
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Affiliation(s)
- F V E Hensling
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, United States of America
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - D Dahliah
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
- Department of Physics, An-Najah National University, Nablus, Palestine
| | - M A Smeaton
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, United States of America
| | - B Shrestha
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, United States of America
- Wright Center for Photovoltaic Innovation and Commercialization, University of Toledo, Toledo, OH 43606, United States of America
| | - V Show
- Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials (PARADIM), Cornell University, Ithaca, NY 14853, United States of America
| | - C T Parzyck
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, United States of America
| | - C Hennighausen
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, United States of America
| | - G N Kotsonis
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, United States of America
| | - G-M Rignanese
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - M R Barone
- Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials (PARADIM), Cornell University, Ithaca, NY 14853, United States of America
| | - I Subedi
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, United States of America
- Wright Center for Photovoltaic Innovation and Commercialization, University of Toledo, Toledo, OH 43606, United States of America
| | - A S Disa
- School of Applied & Engineering Physics, Cornell University, Ithaca, NY 14853, United States of America
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, United States of America
| | - K M Shen
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, United States of America
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, United States of America
| | - B D Faeth
- Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials (PARADIM), Cornell University, Ithaca, NY 14853, United States of America
| | - A T Bollinger
- Brookhaven National Laboratory, Upton, NY 11973, United States of America
| | - I Božović
- Brookhaven National Laboratory, Upton, NY 11973, United States of America
- Department of Chemistry, Yale University, New Haven, CT 06520, United States of America
- Energy Sciences Institute, Yale University, West Haven, CT 06516, United States of America
| | - N J Podraza
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, United States of America
- Wright Center for Photovoltaic Innovation and Commercialization, University of Toledo, Toledo, OH 43606, United States of America
| | - L F Kourkoutis
- School of Applied & Engineering Physics, Cornell University, Ithaca, NY 14853, United States of America
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, United States of America
| | - G Hautier
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, United States of America
| | - D G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, United States of America
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, United States of America
- Leibniz-Institut für Kristallzüchtung, Max-Born-Strasse 2, 12849 Berlin, Germany
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Jaszewski ST, Calderon S, Shrestha B, Fields SS, Samanta A, Vega FJ, Minyard JD, Casamento JA, Maria JP, Podraza NJ, Dickey EC, Rappe AM, Beechem TE, Ihlefeld JF. Infrared Signatures for Phase Identification in Hafnium Oxide Thin Films. ACS Nano 2023. [PMID: 38015799 DOI: 10.1021/acsnano.3c08371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
Phase identification in HfO2-based thin films is a prerequisite to understanding the mechanisms stabilizing the ferroelectric phase in these materials, which hold great promise in next-generation nonvolatile memory and computing technology. While grazing-incidence X-ray diffraction is commonly employed for this purpose, it has difficulty unambiguously differentiating between the ferroelectric phase and other metastable phases that may exist due to similarities in the d-spacings, their low intensities, and the overlapping of reflections. Infrared signatures provide an alternative route. However, their use in phase identification remains limited because phase control has overwhelmingly been accomplished via substituents, thereby convoluting infrared signatures between the substituents and the phase changes that they induce. Herein, we report the infrared optical responses of three undoped hafnium oxide films where annealing conditions have been used to create films consisting primarily of the ferroelectric polar orthorhombic Pca21, antipolar orthorhombic Pbca, and monoclinic P21/c phases, as was confirmed via transmission electron microscopy (TEM), UV-visible optical properties, and electrical property measurements. Vibrational signatures acquired from synchrotron nano-Fourier transform infrared spectroscopy (nano-FTIR) are shown to be capable of differentiating between the phases in a nondestructive, rapid, and nanoscale manner. The utility of nano-FTIR is illustrated for a film exhibiting an antiferroelectric polarization response. In this sample, it is proven that this behavior results from the Pbca phase rather than the often-cited tetragonal phase. By demonstrating that IR spectroscopy can unambiguously distinguish phases in this material, this work establishes a tool needed to isolate the factors dictating the ferroelectric phase stability in HfO2-based materials.
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Affiliation(s)
- Samantha T Jaszewski
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
- Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Sebastian Calderon
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Bishal Shrestha
- Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
- Wright Center for Photovoltaic Innovation & Commercialization, University of Toledo, Toledo, Ohio 43606, United States
| | - Shelby S Fields
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Atanu Samanta
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Fernando J Vega
- School of Mechanical Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jacob D Minyard
- School of Mechanical Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Joseph A Casamento
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jon-Paul Maria
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nikolas J Podraza
- Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, United States
- Wright Center for Photovoltaic Innovation & Commercialization, University of Toledo, Toledo, Ohio 43606, United States
| | - Elizabeth C Dickey
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Andrew M Rappe
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Thomas E Beechem
- School of Mechanical Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jon F Ihlefeld
- Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
- Charles L. Brown Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia 22904, United States
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3
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Jayswal NK, Adhikari D, Subedi I, Shan A, Podraza NJ. Role of CdTe Interface Structure on CdS/CdTe Photovoltaic Device Performance. Materials (Basel) 2023; 16:6812. [PMID: 37895793 PMCID: PMC10608695 DOI: 10.3390/ma16206812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 10/15/2023] [Accepted: 10/17/2023] [Indexed: 10/29/2023]
Abstract
Glancing angle deposition (GLAD) of CdTe can produce a cubic, hexagonal, or mixed phase crystal structure depending upon the oblique deposition angles (Φ) and substrate temperature. GLAD CdTe films are prepared at different Φ at room temperature (RT) and a high temperature (HT) of 250 °C and used as interlayers between the n-type hexagonal CdS window layer and the p-type cubic CdTe absorber layer to investigate the role of interfacial tailoring at the CdS/CdTe heterojunction in photovoltaic (PV) device performance. The Φ = 80° RT GLAD CdTe interlayer and CdS both have the hexagonal structure, which reduces lattice mismatch at the CdS/CdTe interface and improves electronic quality at the heterojunction for device performance optimization. The device performance of HT CdS/CdTe solar cells with Φ = 80° RT with 50 to 350 nm thick GLAD CdTe interlayers is evaluated in which a 250 nm interlayer device shows the best device performance with a 0.53 V increase in open-circuit voltage and fill-factor product and a 0.73% increase in absolute efficiency compared to the HT baseline PV device without an interlayer.
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Affiliation(s)
| | | | | | | | - Nikolas J. Podraza
- Department of Physics and Astronomy, Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA; (N.K.J.); (D.A.); (I.S.)
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4
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Dou Y, Tumusange MS, Jin J, Wang X, Crater ER, Liu S, Zhu L, Zuberi S, Harman G, Weaver C, Ramanujam B, Shan A, Moore RB, Podraza NJ, Yan Y, Quan L. Broadband Achromatic Quarter-Waveplate Using 2D Hybrid Copper Halide Single Crystals. J Am Chem Soc 2023; 145:18007-18014. [PMID: 37540785 DOI: 10.1021/jacs.3c05705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2023]
Abstract
Achromatic quarter waveplates (A-QWPs), traditionally constructed from multiple birefringent crystals, can modulate light polarization and retardation across a broad range of wavelengths. This mechanism is inherently related to phase retardation controlled by the fast and slow axis of stacked multi-birefringent crystals. However, the conventional design of A-QWPs requires the incorporation of multiple birefringent crystals, which complicates the manufacturing process and raises costs. Here, we report the discovery of a broadband (540-1060 nm) A-QWP based on a two-dimensional (2D) layered hybrid copper halide (HCH) perovskite single crystal. The 2D copper chloride (CuCl6) layers of the HCH crystal undergo Jahn-Teller distortion and subsequently trigger the in-plane optical birefringence. Its broad range of the wavelength response as an A-QWP is a consequence of the out-of-plane mosaicity formed among the stacked inorganic layers during the single-crystal self-assembly process in the solution phase. Given the versatility of 2D hybridhalide perovskites, the 2D HCH crystal offers a promising approach for designing cost-effective A-QWPs and the ability to integrate other optical devices.
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Affiliation(s)
- Yixuan Dou
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Marie Solange Tumusange
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Jianbo Jin
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Xiaoming Wang
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Erin R Crater
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Sunhao Liu
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Liyan Zhu
- The Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Samir Zuberi
- College of Science in the Academy of Integrated Science, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Gavin Harman
- Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Conner Weaver
- The Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Balaji Ramanujam
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Ambalanath Shan
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Robert B Moore
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, 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
| | - Yanfa Yan
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Lina Quan
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Materials and Science Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
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5
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Chen H, Maxwell A, Li C, Teale S, Chen B, Zhu T, Ugur E, Harrison G, Grater L, Wang J, Wang Z, Zeng L, Park SM, Chen L, Serles P, Awni RA, Subedi B, Zheng X, Xiao C, Podraza NJ, Filleter T, Liu C, Yang Y, Luther JM, De Wolf S, Kanatzidis MG, Yan Y, Sargent EH. Publisher Correction: Regulating surface potential maximizes voltage in all-perovskite tandems. Nature 2023; 620:E15. [PMID: 37488360 DOI: 10.1038/s41586-023-06450-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Affiliation(s)
- Hao Chen
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Aidan Maxwell
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Chongwen Li
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, USA
| | - Sam Teale
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Bin Chen
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
- Department of Chemistry, Northwestern University, Evanston, IL, USA
| | - Tong Zhu
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Esma Ugur
- KAUST Solar Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - George Harrison
- KAUST Solar Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - Luke Grater
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Junke Wang
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Zaiwei Wang
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Lewei Zeng
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - So Min Park
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Lei Chen
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, USA
| | - Peter Serles
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Rasha Abbas Awni
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, USA
| | - Biwas Subedi
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, USA
| | | | | | - Nikolas J Podraza
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, USA
| | - Tobin Filleter
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Cheng Liu
- Department of Chemistry, Northwestern University, Evanston, IL, USA
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, USA
| | - Yi Yang
- Department of Chemistry, Northwestern University, Evanston, IL, USA
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, USA
| | | | - Stefaan De Wolf
- KAUST Solar Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | | | - Yanfa Yan
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, USA.
| | - Edward H Sargent
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada.
- Department of Chemistry, Northwestern University, Evanston, IL, USA.
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, USA.
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6
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Bordovalos A, Subedi B, Chen L, Song Z, Yan Y, Podraza NJ. Implications of Electron Transport Layer and Back Metal Contact Variations in Tin-Lead Perovskite Solar Cells Assessed by Spectroscopic Ellipsometry and External Quantum Efficiency. ACS Appl Mater Interfaces 2023; 15:19730-19740. [PMID: 37022937 DOI: 10.1021/acsami.3c01849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The structural and optical properties of hybrid organic-inorganic metal halide perovskite solar cells are measured by spectroscopic ellipsometry to reveal an optically distinct interfacial layer among the back contact metal, charge transport, and absorber layers. Understanding how this interfacial layer impacts performance is essential for developing higher performing solar cells. This interfacial layer is modeled by Bruggeman effective medium approximations (EMAs) to contain perovskite, C60, BCP, and metal. External quantum efficiency (EQE) simulations that consider scattering, electronic losses, and the formation of nonparallel interfaces are created with input derived from ellipsometry structural-optical models and compared with experimental EQE to estimate optical losses. This nonplanar interface causes optical losses in short circuit current density (JSC) of up to 1.2 mA cm-2. A study of glass/C60/SnO2/Ag or Cu and glass/C60/BCP/Ag film stacks shows that C60 and BCP mix, but replacing BCP with SnO2 can prevent mixing between the ETLs to prevent contact between C60 and back contact metal and enable the formation of a planar interface between ETLs and back contact metals.
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Affiliation(s)
- Alexander Bordovalos
- Department of Physics and Astronomy & Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, United States
| | - Biwas Subedi
- Department of Physics and Astronomy & Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, United States
| | - Lei Chen
- 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
| | - Yanfa Yan
- Department of Physics and Astronomy & Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, United States
| | - Nikolas J Podraza
- 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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Wang Z, Zeng L, Zhu T, Chen H, Chen B, Kubicki DJ, Balvanz A, Li C, Maxwell A, Ugur E, Dos Reis R, Cheng M, Yang G, Subedi B, Luo D, Hu J, Wang J, Teale S, Mahesh S, Wang S, Hu S, Jung E, Wei M, Park SM, Grater L, Aydin E, Song Z, Podraza NJ, Lu ZH, Huang J, Dravid VP, De Wolf S, Yan Y, Grätzel M, Kanatzidis M, Sargent E. Suppressed phase segregation for triple-junction perovskite solar cells. Nature 2023:10.1038/s41586-023-06006-7. [PMID: 36977463 DOI: 10.1038/s41586-023-06006-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 03/23/2023] [Indexed: 03/30/2023]
Abstract
The tunable band gaps and facile fabrication of perovskites make them attractive for multi-junction photovoltaics1,2. However, light-induced phase segregation limits their efficiency and stability3-5: this occurs in wide band gap (> 1.65 eV) I/Br mixed perovskite absorbers, and becomes even more acute in the top cells of triple-junction solar photovoltaics that requires a fully 2.0 eV band gap absorber2,6. We report herein that lattice distortion in I/Br mixed perovskites is correlated with the suppression of phase segregation, generating an increased ion migration energy barrier arising from the decreased average interatomic distance between A-site cation and iodide. Using a ~2.0 eV Rb/Cs mixed-cation inorganic perovskite with large lattice distortion in the top subcell, we fabricated all-perovskite triple-junction solar cells and achieved an efficiency of 24.3% (23.3% certified quasi-steady-state efficiency) with an open-circuit voltage of 3.21 V. This is, to our knowledge, the first reported certified efficiency for perovskite-based triple-junction solar cells. The triple-junction devices retain 80% of their initial efficiency following 420 hours of operation at the maximum power point.
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Affiliation(s)
- Zaiwei Wang
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Lewei Zeng
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Tong Zhu
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Hao Chen
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Bin Chen
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
- Department of Chemistry, Northwestern University, Evanston, Illinois, USA
| | - Dominik J Kubicki
- Department of Physics, University of Warwick, Coventry, United Kingdom
| | - Adam Balvanz
- Department of Chemistry, Northwestern University, Evanston, Illinois, USA
| | - Chongwen Li
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio, USA
| | - Aidan Maxwell
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Esma Ugur
- KAUST Solar Center (KSC), Physical Sciences and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Roberto Dos Reis
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois, USA
| | - Matthew Cheng
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois, USA
| | - Guang Yang
- Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Biwas Subedi
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio, USA
| | - Deying Luo
- Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Juntao Hu
- Department of Physics, Center for Optoelectronics Engineering Research, Yunnan University, Kunming, China
| | - Junke Wang
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Sam Teale
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Suhas Mahesh
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Sasa Wang
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Shuangyan Hu
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Euidae Jung
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Mingyang Wei
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
- Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fedérale de Lausanne (EPFL), Lausanne, Switzerland
| | - So Min Park
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Luke Grater
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada
| | - Erkan Aydin
- KAUST Solar Center (KSC), Physical Sciences and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Zhaoning Song
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio, USA
| | - Nikolas J Podraza
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio, USA
| | - Zheng-Hong Lu
- Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario, Canada
- Department of Physics, Center for Optoelectronics Engineering Research, Yunnan University, Kunming, China
| | - Jinsong Huang
- Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Vinayak P Dravid
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois, USA
| | - Stefaan De Wolf
- KAUST Solar Center (KSC), Physical Sciences and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Yanfa Yan
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio, USA
| | - Michael Grätzel
- Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fedérale de Lausanne (EPFL), Lausanne, Switzerland
| | | | - Edward Sargent
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario, Canada.
- Department of Chemistry, Northwestern University, Evanston, Illinois, USA.
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois, USA.
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8
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Chen H, Maxwell A, Li C, Teale S, Chen B, Zhu T, Ugur E, Harrison G, Grater L, Wang J, Wang Z, Zeng L, Park SM, Chen L, Serles P, Awni RA, Subedi B, Zheng X, Xiao C, Podraza NJ, Filleter T, Liu C, Yang Y, Luther JM, De Wolf S, Kanatzidis MG, Yan Y, Sargent EH. Regulating surface potential maximizes voltage in all-perovskite tandems. Nature 2023; 613:676-681. [PMID: 36379225 DOI: 10.1038/s41586-022-05541-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022]
Abstract
The open-circuit voltage (VOC) deficit in perovskite solar cells is greater in wide-bandgap (over 1.7 eV) cells than in perovskites of roughly 1.5 eV (refs. 1,2). Quasi-Fermi-level-splitting measurements show VOC-limiting recombination at the electron-transport-layer contact3-5. This, we find, stems from inhomogeneous surface potential and poor perovskite-electron transport layer energetic alignment. Common monoammonium surface treatments fail to address this; as an alternative, we introduce diammonium molecules to modify perovskite surface states and achieve a more uniform spatial distribution of surface potential. Using 1,3-propane diammonium, quasi-Fermi-level splitting increases by 90 meV, enabling 1.79 eV perovskite solar cells with a certified 1.33 V VOC and over 19% power conversion efficiency (PCE). Incorporating this layer into a monolithic all-perovskite tandem, we report a record VOC of 2.19 V (89% of the detailed balance VOC limit) and over 27% PCE (26.3% certified quasi-steady state). These tandems retained more than 86% of their initial PCE after 500 h of operation.
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Affiliation(s)
- Hao Chen
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Aidan Maxwell
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Chongwen Li
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada.,Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, USA
| | - Sam Teale
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Bin Chen
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada.,Department of Chemistry, Northwestern University, Evanston, IL, USA
| | - Tong Zhu
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Esma Ugur
- KAUST Solar Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - George Harrison
- KAUST Solar Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - Luke Grater
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Junke Wang
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Zaiwei Wang
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Lewei Zeng
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - So Min Park
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Lei Chen
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, USA
| | - Peter Serles
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Rasha Abbas Awni
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, USA
| | - Biwas Subedi
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, USA
| | | | | | - Nikolas J Podraza
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, USA
| | - Tobin Filleter
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Cheng Liu
- Department of Chemistry, Northwestern University, Evanston, IL, USA.,Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, USA
| | - Yi Yang
- Department of Chemistry, Northwestern University, Evanston, IL, USA.,Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, USA
| | | | - Stefaan De Wolf
- KAUST Solar Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | | | - Yanfa Yan
- Department of Physics and Astronomy and Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH, USA.
| | - Edward H Sargent
- The Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada. .,Department of Chemistry, Northwestern University, Evanston, IL, USA. .,Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, USA.
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9
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Jellison GE, Podraza NJ, Shan A. Ellipsometry: dielectric functions of anisotropic crystals and symmetry. J Opt Soc Am A Opt Image Sci Vis 2022; 39:2225-2237. [PMID: 36520740 DOI: 10.1364/josaa.471958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/06/2022] [Indexed: 06/17/2023]
Abstract
The optical functions of anisotropic materials can be determined using generalized ellipsometry, which can measure the cross-polarization coefficients (CPs) of the sample surface reflections. These CPs have several symmetry relations with respect to the symmetry of the crystal. This paper explores the symmetry relations of these CPs for uniaxial, orthorhombic, and monoclinic crystals and the requirements for generalized ellipsometry. Several ellipsometry measurement configurations are examined, including the requirements for the accurate measurements of the dielectric functions of anisotropic crystals.
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10
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Subedi B, Li C, Chen C, Liu D, Junda MM, Song Z, Yan Y, Podraza NJ. Urbach Energy and Open-Circuit Voltage Deficit for Mixed Anion-Cation Perovskite Solar Cells. ACS Appl Mater Interfaces 2022; 14:7796-7804. [PMID: 35129320 DOI: 10.1021/acsami.1c19122] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [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 Urbach energy indicating the width of the exponentially decaying sub-bandgap absorption tail is commonly used as the indicator of electronic quality of thin-film materials used as absorbers in solar cells. Urbach energies of hybrid inorganic-organic metal halide perovskites with various anion-cation compositions are measured by photothermal deflection spectroscopy. The variation in anion-cation composition has a substantial effect on the measured Urbach energy and hence the electronic quality of the perovskite. Depending upon the compositions, the Urbach energy varies from 18 to 65 meV for perovskite films with similar bandgap energies. For most of the perovskite compositions studied here including methylammonium (MA) + formamidinium (FA)-based Pb iodides, mixed Sn + Pb narrow-bandgap perovskites with low or intermediate Sn contents, and wide-bandgap FA + Cs- and I + Br-based perovskites, the correlation between the Urbach energy of the perovskite thin film and open-circuit voltage (VOC) deficit for corresponding solar cells shows a direct relationship with reduction of the Urbach energy occurring with a beneficial decrease in the VOC deficit. However, due to issues related to material quality, impurity phases and stability in laboratory ambient air, and unoptimized film processing techniques, the solar cells incorporating Cs-based inorganic and mixed Sn + Pb perovskites with a higher than optimum Sn content show a higher VOC deficit even though the corresponding films show a lower Urbach energy.
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Affiliation(s)
- Biwas Subedi
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, United States
| | - Chongwen Li
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, United States
| | - Cong Chen
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, United States
| | - Dachang Liu
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, United States
| | - Maxwell M Junda
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, United States
| | - Zhaoning Song
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, United States
| | - Yanfa Yan
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, United States
| | - Nikolas J Podraza
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, United States
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11
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Kaya H, Ngo D, Hahn SH, Li M, He H, Yedikardeş B, Sökmen İ, Pester CW, Podraza NJ, Gin S, Kim SH. Estimating Internal Stress of an Alteration Layer Formed on Corroded Boroaluminosilicate Glass through Spectroscopic Ellipsometry Analysis. ACS Appl Mater Interfaces 2021; 13:50470-50480. [PMID: 34643085 DOI: 10.1021/acsami.1c10134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Aqueous corrosion of glass may result in the formation of an alteration layer in the glass surface of which chemical composition and network structure are different from those of the bulk glass. Since corrosion occurs far below the glass-transition temperature, the alteration layer cannot fully relax to the new structure with the lowest possible energy. Molecular dynamics simulations suggested that such a network will contain highly strained chemical bonds, which can be manifested as a stress in the alteration layer. Common techniques to measure stress in thin films or surface layers were found inadequate for thick monolithic glass samples corroded in water. Here, we explored the use of spectroscopic ellipsometry to test the presence of internal stress in the alteration layer formed by aqueous corrosion of glass. A procedure for analyses of spectroscopic ellipsometry data to determine birefringence in the alteration layer was developed. Findings with the established fitting procedure suggested that a stress builds up in the corroded surface layer of a boroaluminosilicate glass if there is a change in relative humidity, pH, or electrolyte concentration of the environment to which the glass surface is exposed. A similar process may occur in other types of glass, and it may affect the surface properties of corroded glass objects.
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Affiliation(s)
- Huseyin Kaya
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Dien Ngo
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Seung Ho Hahn
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mingxiao Li
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Hongtu He
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Key Laboratory of Testing Technology for Manufacturing Process, Ministry of Education, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China
| | - Beyza Yedikardeş
- Şişecam Science and Technology Center, Şişecam Str., No:2 Çayırova, Kocaeli 41400, Turkey
| | - İlkay Sökmen
- Şişecam Science and Technology Center, Şişecam Str., No:2 Çayırova, Kocaeli 41400, Turkey
| | - Christian W Pester
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nikolas J Podraza
- Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606, United States
- Wright Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States
| | - Stephane Gin
- CEA, DES, ISEC, DE2D, University of Montpellier, Marcoule, Bagnols sur Cèze F-30207, France
| | - Seong H Kim
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Chemical Engineering and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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12
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Shan A, Ramanujam B, Podraza NJ, Collins RW. Analysis of non-idealities in rhomb compensators. Opt Express 2021; 29:36328-36352. [PMID: 34809046 DOI: 10.1364/oe.440680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
In-line rotatable rhombs that are only weakly chromatic are desired as compensators for a wide variety of applications in spectroscopic polarimetry and Mueller matrix spectroscopic ellipsometry. These devices employ multiple total internal reflections to generate differences in the phase shifts upon reflection for orthogonal fast and slow axis optical electric field components. A framework has been developed for characterization of non-idealities in the performance of rhombs due to dissipation and associated dichroism upon each reflection as well as stress-induced birefringence along each beam path. External oblique reflection measurements by spectroscopic ellipsometry for the internally reflecting interface structures has enabled characterization of the dichroic effects and retardance generated by the reflections. The framework for analysis of the effects of stress relies on simulations demonstrating that the contributions to polarization modification from each beam path depend only on the accumulated stress-induced retardance and average azimuthal angle of the fast principal stress axis along the given path. The overall approach has been applied to straight-through Mueller matrix measurements of a three-reflection rhomb in its operational configuration to establish the set of stress parameters for each of the four beam paths needed to fit the measurements. Thus, device geometry and optical structure, including layer thicknesses and component media optical properties, as well as stress-induced retardances and average stress azimuthal angles, which are all deduced in the analysis, enable a complete description of the polarization modifying properties of the rhomb when serving as a compensator.
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13
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Alaani MAR, Koirala P, Phillips AB, Liyanage GK, Awni RA, Sapkota DR, Ramanujam B, Heben MJ, O’Leary SK, Podraza NJ, Collins RW. Optical Properties of Magnesium-Zinc Oxide for Thin Film Photovoltaics. Materials (Basel) 2021; 14:ma14195649. [PMID: 34640041 PMCID: PMC8510442 DOI: 10.3390/ma14195649] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 12/28/2022]
Abstract
Motivated by their utility in CdTe-based thin film photovoltaics (PV) devices, an investigation of thin films of the magnesium-zinc oxide (MgxZn1−xO or MZO) alloy system was undertaken applying spectroscopic ellipsometry (SE). Dominant wurtzite phase MZO thin films with Mg contents in the range 0 ≤ x ≤ 0.42 were deposited on room temperature soda lime glass (SLG) substrates by magnetron co-sputtering of MgO and ZnO targets followed by annealing. The complex dielectric functions ε of these films were determined and parameterized over the photon energy range from 0.73 to 6.5 eV using an analytical model consisting of two critical point (CP) oscillators. The CP parameters in this model are expressed as polynomial functions of the best fitting lowest CP energy or bandgap E0 = Eg, which in turn is a quadratic function of x. As functions of x, both the lowest energy CP broadening and the Urbach parameter show minima for x ~ 0.3, which corresponds to a bandgap of 3.65 eV. As a result, it is concluded that for this composition and bandgap, the MZO exhibits either a minimum concentration of defects in the bulk of the crystallites or a maximum in the grain size, an observation consistent with measured X-ray diffraction line broadenings. The parametric expression for ε developed here is expected to be useful in future mapping and through-the-glass SE analyses of partial and complete PV device structures incorporating MZO.
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Affiliation(s)
- Mohammed A. Razooqi Alaani
- Wright Center for Photovoltaics Innovation & Commercialization, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA; (P.K.); (A.B.P.); (G.K.L.); (R.A.A.); (D.R.S.); (B.R.); (M.J.H.)
- Correspondence: (M.A.R.A.); (N.J.P.); (R.W.C.)
| | - Prakash Koirala
- Wright Center for Photovoltaics Innovation & Commercialization, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA; (P.K.); (A.B.P.); (G.K.L.); (R.A.A.); (D.R.S.); (B.R.); (M.J.H.)
| | - Adam B. Phillips
- Wright Center for Photovoltaics Innovation & Commercialization, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA; (P.K.); (A.B.P.); (G.K.L.); (R.A.A.); (D.R.S.); (B.R.); (M.J.H.)
| | - Geethika K. Liyanage
- Wright Center for Photovoltaics Innovation & Commercialization, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA; (P.K.); (A.B.P.); (G.K.L.); (R.A.A.); (D.R.S.); (B.R.); (M.J.H.)
| | - Rasha A. Awni
- Wright Center for Photovoltaics Innovation & Commercialization, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA; (P.K.); (A.B.P.); (G.K.L.); (R.A.A.); (D.R.S.); (B.R.); (M.J.H.)
| | - Dhurba R. Sapkota
- Wright Center for Photovoltaics Innovation & Commercialization, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA; (P.K.); (A.B.P.); (G.K.L.); (R.A.A.); (D.R.S.); (B.R.); (M.J.H.)
| | - Balaji Ramanujam
- Wright Center for Photovoltaics Innovation & Commercialization, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA; (P.K.); (A.B.P.); (G.K.L.); (R.A.A.); (D.R.S.); (B.R.); (M.J.H.)
| | - Michael J. Heben
- Wright Center for Photovoltaics Innovation & Commercialization, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA; (P.K.); (A.B.P.); (G.K.L.); (R.A.A.); (D.R.S.); (B.R.); (M.J.H.)
| | - Stephen K. O’Leary
- School of Engineering, The University of British Columbia Okanagan, 3333 University Way, Kelowna, BC V1V 1V7, Canada;
| | - Nikolas J. Podraza
- Wright Center for Photovoltaics Innovation & Commercialization, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA; (P.K.); (A.B.P.); (G.K.L.); (R.A.A.); (D.R.S.); (B.R.); (M.J.H.)
- Correspondence: (M.A.R.A.); (N.J.P.); (R.W.C.)
| | - Robert W. Collins
- Wright Center for Photovoltaics Innovation & Commercialization, Department of Physics & Astronomy, University of Toledo, Toledo, OH 43606, USA; (P.K.); (A.B.P.); (G.K.L.); (R.A.A.); (D.R.S.); (B.R.); (M.J.H.)
- Correspondence: (M.A.R.A.); (N.J.P.); (R.W.C.)
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14
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Subedi B, Song Z, Chen C, Li C, Ghimire K, Junda MM, Subedi I, Yan Y, Podraza NJ. Optical and Electronic Losses Arising from Physically Mixed Interfacial Layers in Perovskite Solar Cells. ACS Appl Mater Interfaces 2021; 13:4923-4934. [PMID: 33470116 DOI: 10.1021/acsami.0c16364] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Perovskite solar cell device performance is affected by optical and electronic losses. To minimize these losses in solar cells, it is important to identify their sources. Here, we report the optical and electronic losses arising from physically mixed interfacial layers between the adjacent component materials in highly efficient two terminal (2T) all-perovskite tandem, single-junction wide-bandgap, and single-junction narrow-bandgap perovskite-based solar cells. Physically mixed interfacial layers as the sources of optical and electronic losses are identified from spectroscopic ellipsometry measurements and data analysis followed by comparisons of simulated and measured external quantum efficiency spectra. Parasitic absorbance in the physically mixed regions between silver metal electrical contacts and electron transport layers (ETLs) near the back contact and a physical mixture of commercial indium tin oxide and hole transport layers (HTL) near the front electrical contact lead to substantial optical loss. A lower-density void + perovskite nucleation layer formed during perovskite deposition at the interface between the perovskite absorber layer and the HTL causes electronic losses because of incomplete collection of photogenerated carriers likely originating from poor coverage and passivation of the initially nucleating grains.
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Affiliation(s)
- Biwas Subedi
- Department of Physics and Astronomy and the Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo 43606, Ohio, United States
| | - Zhaoning Song
- Department of Physics and Astronomy and the Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo 43606, Ohio, United States
| | - Cong Chen
- Department of Physics and Astronomy and the Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo 43606, Ohio, United States
| | - Chongwen Li
- Department of Physics and Astronomy and the Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo 43606, Ohio, United States
| | - Kiran Ghimire
- Department of Physics and Astronomy and the Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo 43606, Ohio, United States
| | - Maxwell M Junda
- Department of Physics and Astronomy and the Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo 43606, Ohio, United States
| | - Indra Subedi
- Department of Physics and Astronomy and the Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo 43606, Ohio, United States
| | - Yanfa Yan
- Department of Physics and Astronomy and the Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo 43606, Ohio, United States
| | - Nikolas J Podraza
- Department of Physics and Astronomy and the Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo 43606, Ohio, United States
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15
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Subedi B, Li C, Junda MM, Song Z, Yan Y, Podraza NJ. Effects of intrinsic and atmospherically induced defects in narrow bandgap (FASnI 3) x(MAPbI 3) 1-x perovskite films and solar cells. J Chem Phys 2020; 152:064705. [PMID: 32061228 DOI: 10.1063/1.5126867] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Narrow bandgap mixed tin (Sn) + lead (Pb) perovskites are necessary for the bottom sub-cell absorber in high efficiency all-perovskite polycrystalline tandem solar cells. We report on the impact of mixed cation composition and atmospheric exposure of perovskite films on sub-gap absorption in films and performance of solar cells based on narrow bandgap mixed formamidinium (FA) + methylammonium (MA) and Sn + Pb halide perovskites, (FASnI3)x(MAPbI3)1-x. Structural and optical properties of 0.3 ≤ x ≤ 0.8 (FASnI3)x(MAPbI3)1-x perovskite thin film absorbers with bandgaps ranging from 1.25 eV (x = 0.6) to 1.34 eV (x = 0.3) are probed with and without atmospheric exposure. Urbach energy, which quantifies the amount of sub-gap absorption, is tracked for pristine perovskite films as a function of composition, with x = 0.6 and 0.3 demonstrating the lowest and highest Urbach energies of 23 meV and 36 meV, respectively. Films with x = 0.5 and 0.6 compositions show less degradation upon atmospheric exposure than higher or lower Sn-content films having greater sub-gap absorption. The corresponding solar cells based on the x = 0.6 absorber show the highest device performance. Despite having a low Urbach energy, higher Sn-content solar cells show reduced device performances as the amount of degradation via oxidation is the most substantial.
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Affiliation(s)
- Biwas Subedi
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, USA
| | - Chongwen Li
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, USA
| | - Maxwell M Junda
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, USA
| | - Zhaoning Song
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, USA
| | - Yanfa Yan
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, USA
| | - Nikolas J Podraza
- Department of Physics and Astronomy and The Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, USA
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16
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Uprety P, Subedi I, Junda MM, Collins RW, Podraza NJ. Photogenerated Carrier Transport Properties in Silicon Photovoltaics. Sci Rep 2019; 9:19015. [PMID: 31831793 PMCID: PMC6908689 DOI: 10.1038/s41598-019-55173-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/22/2019] [Indexed: 11/29/2022] Open
Abstract
Electrical transport parameters for active layers in silicon (Si) wafer solar cells are determined from free carrier optical absorption using non-contacting optical Hall effect measurements. Majority carrier transport parameters [carrier concentration (N), mobility (μ), and conductivity effective mass (m*)] are determined for both the n-type emitter and p-type bulk wafer Si of an industrially produced aluminum back surface field (Al-BSF) photovoltaic device. From measurements under 0 and ±1.48 T external magnetic fields and nominally “dark” conditions, the following respective [n, p]-type Si parameters are obtained: N = [(3.6 ± 0.1) × 1018 cm−3, (7.6 ± 0.1) × 1015 cm−3]; μ = [166 ± 6 cm2/Vs, 532 ± 12 cm2/Vs]; and m* = [(0.28 ± 0.03) × me, (0.36 ± 0.02) × me]. All values are within expectations for this device design. Contributions from photogenerated carriers in both regions of the p-n junction are obtained from measurements of the solar cell under “light” 1 sun illumination (AM1.5 solar irradiance spectrum). From analysis of combined dark and light optical Hall effect measurements, photogenerated minority carrier transport parameters [minority carrier concentration (Δp or Δn) and minority carrier mobility (μh or μe)] under 1 sun illumination for both n- and p-type Si components of the solar cell are determined. Photogenerated minority carrier concentrations are [(7.8 ± 0.2) × 1016 cm−3, (2.2 ± 0.2) × 1014 cm−3], and minority carrier mobilities are [331 ± 191 cm2/Vs, 766 ± 331 cm2/Vs], for the [n, p]-type Si, respectively, values that are within expectations from literature. Using the dark majority carrier concentration and the effective equilibrium minority carrier concentration under 1 sun illumination, minority carrier effective lifetime and diffusion length are calculated in the n-type emitter and p-type wafer Si with the results also being consistent with literature. Solar cell device performance parameters including photovoltaic device efficiency, open circuit voltage, fill factor, and short circuit current density are also calculated from these transport parameters obtained via optical Hall effect using the diode equation and PC1D solar cell simulations. The calculated device performance parameters are found to be consistent with direct current-voltage measurement demonstrating the validity of this technique for electrical transport property measurements of the semiconducting layers in complete Si solar cells. To the best of our knowledge, this is the first method that enables determination of both minority and majority carrier transport parameters in both active layers of the p-n junction in a complete solar cell.
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Affiliation(s)
- Prakash Uprety
- Wright Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH, 43606, USA
| | - Indra Subedi
- Wright Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH, 43606, USA
| | - Maxwell M Junda
- Wright Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH, 43606, USA
| | - Robert W Collins
- Wright Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH, 43606, USA
| | - Nikolas J Podraza
- Wright Center for Photovoltaics Innovation and Commercialization & Department of Physics and Astronomy, University of Toledo, Toledo, OH, 43606, USA.
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Adhikari D, Junda MM, Grice CR, Marsillac SX, Collins RW, Podraza NJ. n-i-p Nanocrystalline Hydrogenated Silicon Solar Cells with RF-Magnetron Sputtered Absorbers. Materials (Basel) 2019; 12:ma12101699. [PMID: 31130599 PMCID: PMC6566675 DOI: 10.3390/ma12101699] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/10/2019] [Accepted: 05/21/2019] [Indexed: 11/26/2022]
Abstract
Nanocrystalline hydrogenated silicon (nc-Si:H) substrate configuration n-i-p solar cells have been fabricated on soda lime glass substrates with active absorber layers prepared by plasma enhanced chemical vapor deposition (PECVD) and radio frequency magnetron sputtering. The cells with nanocrystalline PECVD absorbers and an untextured back reflector serve as a baseline for comparison and have power conversion efficiency near 6%. By comparison, cells with sputtered absorbers achieved efficiencies of about 1%. Simulations of external quantum efficiency (EQE) are compared to experimental EQE to determine a carrier collection probability gradient with depth for the device with the sputtered i-layer absorber. This incomplete collection of carriers generated in the absorber is most pronounced in material near the n/i interface and is attributed to breaking vacuum between deposition of layers for the sputtered absorbers, possible low electronic quality of the nc-Si:H sputtered absorber, and damage at the n/i interface by over-deposition of the sputtered i-layer during device fabrication.
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Affiliation(s)
- Dipendra Adhikari
- Department of Physics & Astronomy and The Wright Center for Photovoltaics Innovation & Commercialization, University of Toledo, Toledo, OH 43606, USA.
| | - Maxwell M Junda
- Department of Physics & Astronomy and The Wright Center for Photovoltaics Innovation & Commercialization, University of Toledo, Toledo, OH 43606, USA.
| | - Corey R Grice
- Department of Physics & Astronomy and The Wright Center for Photovoltaics Innovation & Commercialization, University of Toledo, Toledo, OH 43606, USA.
| | - Sylvain X Marsillac
- Virginia Institute of Photovoltaics, Old Dominion University, Norfolk, VA 23529, USA.
| | - Robert W Collins
- Department of Physics & Astronomy and The Wright Center for Photovoltaics Innovation & Commercialization, University of Toledo, Toledo, OH 43606, USA.
| | - Nikolas J Podraza
- Department of Physics & Astronomy and The Wright Center for Photovoltaics Innovation & Commercialization, University of Toledo, Toledo, OH 43606, USA.
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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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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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Subedi I, Bhandari KP, Ellingson RJ, Podraza NJ. Near infrared to ultraviolet optical properties of bulk single crystal and nanocrystal thin film iron pyrite. Nanotechnology 2016; 27:295702. [PMID: 27285310 DOI: 10.1088/0957-4484/27/29/295702] [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 report optical properties of iron pyrite (FeS2) determined from ex situ spectroscopic ellipsometry measurements made on both a commercially available bulk single crystal and nanocrystalline thin film over a spectral range of 0.735-5.887 eV. The complex dielectric function, ε (E) = ε 1 (E) + iε 2 (E), spectra have been determined by fitting a layered parametric model to the ellipsometric measurements. Spectra in ε are modeled using a Kramers-Kronig consistent critical point parabolic band model involving seven critical points for the bulk single crystal and four critical points for the nanocrystalline film. Absorption coefficient spectra for both types of samples are also determined from ε. Critical point features in the nanocrystalline films are broader, have lower amplitude and lower energy critical points detected having a small blue shift when compared to the single crystal sample.
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Affiliation(s)
- Indra Subedi
- Department of Physics and Astronomy & Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, OH 43606, USA
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21
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Zhang L, Zhou Y, Guo L, Zhao W, Barnes A, Zhang HT, Eaton C, Zheng Y, Brahlek M, Haneef HF, Podraza NJ, Chan MHW, Gopalan V, Rabe KM, Engel-Herbert R. Correlated metals as transparent conductors. Nat Mater 2016; 15:204-10. [PMID: 26657329 DOI: 10.1038/nmat4493] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 10/27/2015] [Indexed: 05/05/2023]
Abstract
The fundamental challenge for designing transparent conductors used in photovoltaics, displays and solid-state lighting is the ideal combination of high optical transparency and high electrical conductivity. Satisfying these competing demands is commonly achieved by increasing carrier concentration in a wide-bandgap semiconductor with low effective carrier mass through heavy doping, as in the case of tin-doped indium oxide (ITO). Here, an alternative design strategy for identifying high-conductivity, high-transparency metals is proposed, which relies on strong electron-electron interactions resulting in an enhancement in the carrier effective mass. This approach is experimentally verified using the correlated metals SrVO3 and CaVO3, which, despite their high carrier concentration (>2.2 × 10(22) cm(-3)), have low screened plasma energies (<1.33 eV), and demonstrate excellent performance when benchmarked against ITO. A method is outlined to rapidly identify other candidates among correlated metals, and strategies are proposed to further enhance their performance, thereby opening up new avenues to develop transparent conductors.
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Affiliation(s)
- Lei Zhang
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Yuanjun Zhou
- Department of Physics and Astronomy, Rutgers University, Rutgers, New Jersey 08854, USA
| | - Lu Guo
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Weiwei Zhao
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Anna Barnes
- Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
- Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, USA
| | - Hai-Tian Zhang
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Craig Eaton
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Yuanxia Zheng
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Matthew Brahlek
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Hamna F Haneef
- Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
- Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, USA
| | - Nikolas J Podraza
- Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606, USA
- Wright Center for Photovoltaics Innovation and Commercialization, University of Toledo, Toledo, Ohio 43606, USA
| | - Moses H W Chan
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Venkatraman Gopalan
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Karin M Rabe
- Department of Physics and Astronomy, Rutgers University, Rutgers, New Jersey 08854, USA
| | - Roman Engel-Herbert
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Yang JC, He Q, Suresha SJ, Kuo CY, Peng CY, Haislmaier RC, Motyka MA, Sheng G, Adamo C, Lin HJ, Hu Z, Chang L, Tjeng LH, Arenholz E, Podraza NJ, Bernhagen M, Uecker R, Schlom DG, Gopalan V, Chen LQ, Chen CT, Ramesh R, Chu YH. Orthorhombic BiFeO3. Phys Rev Lett 2012; 109:247606. [PMID: 23368382 DOI: 10.1103/physrevlett.109.247606] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/07/2012] [Indexed: 05/12/2023]
Abstract
A new orthorhombic phase of the multiferroic BiFeO3 has been created via strain engineering by growing it on a NdScO(3)(110)(o) substrate. The tensile-strained orthorhombic BiFeO3 phase is ferroelectric and antiferromagnetic at room temperature. A combination of nonlinear optical second harmonic generation and piezoresponse force microscopy revealed that the ferroelectric polarization in the orthorhombic phase is along the in-plane {110}(pc) directions. In addition, the corresponding rotation of the antiferromagnetic axis in this new phase was observed using x-ray linear dichroism.
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Affiliation(s)
- J C Yang
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 300, Taiwan
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Podraza NJ, Wronski CR, Horn MW, Collins RW. Dielectric Functions of a-Si1-xGex:H versus Ge Content, Temperature, and Processing: Advances in Optical Function Parameterization. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-0910-a10-01] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractWe have applied an advanced model to analyze the dielectric functions e = e1 + ie2 of amorphous silicon-germanium alloys (a-Si1-xGex:H) (i) as a function of alloy content × by varying the flow ratio G = [GeH4]/{[SiH4]+[GeH4]} in plasma-enhanced chemical vapor deposition (PECVD), and (ii) for the first time as a function of the measurement temperature Tm by cooling the newly-deposited film. All e spectra (1.5 − 4.5 eV) have been measured by spectroscopic ellipsometry (SE) either in real time during deposition or in situ post-deposition in order to avoid surface contamination. From the resulting extensive database, the optical properties of the alloys can be predicted for any value × and Tm within the ranges of the database. Such a capability is expected to be useful, for example, in real time control of optical gap in the PECVD process and in predicting the quantum efficiency of multijunction a-Si:H-based solar cells versus operating temperature. The effect on the database of other deposition parameters such as the electrode configuration and the H2-dilution ratio R = [H2]/{[SiH4]+ [GeH4]} have also been explored. The latter two studies provide useful insights into materials properties that can be extracted from a single spectroscopic measurement performed in real time during PECVD. For example, the energy width of the resonance in e correlates closely with the precursor surface diffusion characteristics observed throughout growth -- both determined from real time SE. This result indicates that short-range ordering in the film is improved when surface diffusion is promoted.
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