R
R. Verma
Researcher at Swiss Federal Laboratories for Materials Science and Technology
Publications - 7
Citations - 930
R. Verma is an academic researcher from Swiss Federal Laboratories for Materials Science and Technology. The author has contributed to research in topics: Copper indium gallium selenide solar cells & Vacuum deposition. The author has an hindex of 6, co-authored 7 publications receiving 846 citations.
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Journal ArticleDOI
Highly efficient Cu(In,Ga)Se2 solar cells grown on flexible polymer films
Adrian Chirila,Stephan Buecheler,Fabian Pianezzi,P. Bloesch,Christina Gretener,Alexander R. Uhl,C.M. Fella,Lukas Kranz,Julian Perrenoud,S. Seyrling,R. Verma,Shiro Nishiwaki,Yaroslav E. Romanyuk,G. Bilger,Ayodhya N. Tiwari +14 more
TL;DR: A strong composition gradient in the absorber layer is identified as the main reason for inferior performance and it is shown that, by adjusting it appropriately, very high efficiencies can be obtained.
Journal ArticleDOI
Cu(In,Ga)Se2 solar cell grown on flexible polymer substrate with efficiency exceeding 17%
Adrian Chirila,P. Bloesch,S. Seyrling,Alexander R. Uhl,Stephan Buecheler,Fabian Pianezzi,C.M. Fella,Julian Perrenoud,Lukas Kranz,R. Verma,D. Guettler,Shiro Nishiwaki,Yaroslav E. Romanyuk,G. Bilger,D. Brémaud,Ayodhya N. Tiwari +15 more
TL;DR: In this article, a Cu(In,Ga)Se 2 thin film solar cell on a polyimide film with a conversion efficiency of 17.1 %, measured under standard test conditions at the European Solar Test Installation (ESTI), is reported.
Journal ArticleDOI
CuIn1−xGaxSe2 growth process modifications: Influences on microstructure, Na distribution, and device properties
S. Seyrling,Adrian Chirila,D. Güttler,P. Blösch,Fabian Pianezzi,R. Verma,S. Bucheler,Shiro Nishiwaki,Yaroslav E. Romanyuk,Peggy Rossbach,Ayodhya N. Tiwari +10 more
TL;DR: In this article, the influence of varying the evaporation profile, especially the Cu excess during growth, on the microstructure of the final CIGS layer, the distribution of sodium through the layer, and on the photovoltaic performance was investigated.
Journal ArticleDOI
Optical, structural, and chemical properties of flash evaporated In2S3 buffer layer for Cu(In,Ga)Se2 solar cells
R. Verma,Debjit Datta,Adrian Chirila,D. Güttler,Julian Perrenoud,Fabian Pianezzi,U. Müller,Satyendra Kumar,Ayodhya N. Tiwari +8 more
TL;DR: In this paper, the optical constants of layers based on Tauc-Lorentz model dielectric function were extracted from spectroscopic ellipsometry measurements and an analytical layer growth model has been proposed supporting the results obtained by various layer characterization techniques.
Proceedings ArticleDOI
Optimization of composition grading in Cu(In,Ga)Se2 for flexible solar cells and modules
Adrian Chirila,D. Guettler,P. Bloesch,Shiro Nishiwaki,S. Seyrling,Stephan Buecheler,R. Verma,Fabian Pianezzi,Yaroslav E. Romanyuk,G. Bilger,R. Ziltener,D. Brémaud,Ayodhya N. Tiwari +12 more
TL;DR: In this article, the authors developed a flexible CIGS solar cell on polyimide film with a record efficiency of 17.6% using a three-stage evaporation process.