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Title: Enhanced photovoltaic performance of nanocrystalline CdTe/ZnO solar cells using sol-gel ZnO and positive bias treatment

The effect of doping and porosity of the n-type ZnO layer on the performance of solution-processed, sintered p-CdTe/n-ZnO nanocrystal photovoltaic (PV) devices is investigated. Amorphous sol-gel ZnO is found to be the best candidate with overall energy conversion efficiencies above 8% obtained if the ZnO is also indium doped. We demonstrate that when such PV devices are left under forward bias (in dark or light), the device efficiency values are raised to at least 9.8%, due to a substantially increased open-circuit voltage and fill-factor. This drastic enhancement is attributed to improved band alignment at the ITO/CdTe interface. The forward-bias treatment is slowly reversed over a period of days to weeks on standing under open circuit conditions, but is readily restored with further voltage treatment. The moderate processing conditions and high efficiency of such devices demonstrate that nanocrystal-based systems are a promising technology for photovoltaics.
Authors:
 [1] ;  [2] ; ; ;  [1] ;  [3]
  1. CSIRO Materials Science and Engineering, Bayview Avenue, Clayton, Victoria 3168 (Australia)
  2. (Australia)
  3. School of Chemistry and Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010 (Australia)
Publication Date:
OSTI Identifier:
22275580
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 18; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; CADMIUM TELLURIDES; CRYSTALS; DOPED MATERIALS; ELECTRIC POTENTIAL; ENERGY CONVERSION; ENERGY EFFICIENCY; FILL FACTORS; HETEROJUNCTIONS; INTERFACES; LAYERS; NANOSTRUCTURES; PHOTOVOLTAIC EFFECT; SOLAR CELLS; SOL-GEL PROCESS; ZINC OXIDES