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Title: Advantage of suppressed non-Langevin recombination in low mobility organic solar cells

Photovoltaic performance in relation to charge transport is studied in efficient (7.6%) organic solar cells (PTB7:PC{sub 71}BM). Both electron and hole mobilities are experimentally measured in efficient solar cells using the resistance dependent photovoltage technique, while the inapplicability of classical techniques, such as space charge limited current and photogenerated charge extraction by linearly increasing voltage is discussed. Limits in the short-circuit current originate from optical losses, while charge transport is shown not to be a limiting process. Efficient charge extraction without recombination can be achieved with a mobility of charge carriers much lower than previously expected. The presence of dispersive transport with strongly distributed mobilities in high efficiency solar cells is demonstrated. Reduced non-Langevin recombination is shown to be beneficial for solar cells with imbalanced, low, and dispersive electron and hole mobilities.
Authors:
; ; ; ; ;  [1] ; ;  [2]
  1. Centre for Organic Photonics and Electronics (COPE), School of Chemistry and Molecular Biosciences and School of Mathematics and Physics, The University of Queensland, Brisbane 4072 (Australia)
  2. School of Engineering and Physical Sciences, James Cook University, Townsville 4811 (Australia)
Publication Date:
OSTI Identifier:
22303956
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 1; 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; CARRIER MOBILITY; CHARGE CARRIERS; CHARGE TRANSPORT; CURRENTS; EFFICIENCY; ELECTRIC POTENTIAL; ELECTRICAL FAULTS; ELECTRONS; EXTRACTION; LOSSES; ORGANIC SOLAR CELLS; PHOTOVOLTAIC EFFECT; RECOMBINATION