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Mapping photovoltaic performance with nanoscale resolution
Author(s) -
Kutes Yasemin,
Aguirre Brandon A.,
Bosse James L.,
CruzCampa Jose L.,
Zubia David,
Huey Bryan D.
Publication year - 2016
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.2698
Subject(s) - photovoltaics , photocurrent , materials science , cadmium telluride photovoltaics , photovoltaic system , open circuit voltage , nanoscopic scale , optoelectronics , biasing , suns in alchemy , short circuit , grain boundary , voltage , maximum power principle , nanotechnology , electrical engineering , composite material , microstructure , engineering
Photo‐conductive AFM spectroscopy (‘pcAFMs’) is proposed as a high‐resolution approach for investigating nanostructured photovoltaics, uniquely providing nanoscale maps of photovoltaic (PV) performance parameters such as the short circuit current, open circuit voltage, maximum power, or fill factor. The method is demonstrated with a stack of 21 images acquired during in situ illumination of micropatterned polycrystalline CdTe/CdS, providing more than 42 000 I / V curves spatially separated by ~5 nm. For these CdTe/CdS microcells, the calculated photoconduction ranges from 0 to 700 picoSiemens (pS) upon illumination with ~1.6 suns, depending on location and biasing conditions. Mean short circuit currents of 2 pA, maximum powers of 0.5 pW, and fill factors of 30% are determined. The mean voltage at which the detected photocurrent is zero is determined to be 0.7 V. Significantly, enhancements and reductions in these more commonly macroscopic PV performance metrics are observed to correlate with certain grains and grain boundaries, and are confirmed to be independent of topography. These results demonstrate the benefits of nanoscale resolved PV functional measurements, reiterate the importance of microstructural control down to the nanoscale for 'PV devices, and provide a widely applicable new approach for directly investigating PV materials. Copyright © 2015 John Wiley & Sons, Ltd.