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Title: Built-in voltage of organic bulk heterojuction p-i-n solar cells measured by electroabsorption spectroscopy

We investigate the influence of the built-in voltage on the performance of organic bulk heterojuction solar cells that are based on a p-i-n structure. Electrical doping in the hole and the electron transport layer allows to tune their work function and hence to adjust the built-in voltage: Changing the doping concentration from 0.5 to 32 wt% induces a shift of the work function towards the transport levels and increases the built-in voltage. To determine the built-in voltage, we use electroabsorption spectroscopy which is based on an evaluation of the spectra caused by a change in absorption due to an electric field (Stark effect). For a model system with a bulk heterojunction of BF-DPB and C{sub 60}, we show that higher doping concentrations in both the electron and the hole transport layer increase the built-in voltage, leading to an enhanced short circuit current and solar cell performance.
Authors:
; ; ; ; ; ; ; ; ;  [1]
  1. Institut für Angewandte Photophysik, Technische Universität Dresden, D-01062 Dresden (Germany)
Publication Date:
OSTI Identifier:
22254154
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 4; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION; ELECTRIC FIELDS; ELECTRIC POTENTIAL; EVALUATION; FULLERENES; SOLAR CELLS; SPECTRA; STARK EFFECT; WORK FUNCTIONS