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Title: Three-dimensional morphology of CuInS{sub 2}:P3HT hybrid blends for photovoltaic applications

Despite potential advantages, the performance of hybrid solar cells with colloidal nanocrystals remains low compared to pure organic solar cells, in particular, when Cd- and Pb-free nanocrystals are employed. To understand this discrepancy, we analyzed possible limiting factors of the performance of hybrid solar cells with CuInS{sub 2} nanoparticles and the polymer poly(3-hexylthiophene) (P3HT). Optimizing the thickness of the active layer indicated that charge transport limits the performance of the solar cells. Since charge transport is among others influenced by the morphology of the bulk heterojunction layer, we performed a detailed analysis of the blend morphology. Therefore, we used electron tomography which provides three-dimensional information on the interpenetrating network formed by the hybrid CuInS{sub 2}:P3HT system. Using statistical methods, we analyzed the distribution of the nanoparticles inside the polymer matrix and the structure of the percolation paths. We found that the morphology appears well suited for application in hybrid solar cells, meaning that other factors must be the bottleneck. Therefore, we investigated in a second step the influence of a post-deposition ligand exchange with acetic acid. This strategy resulted in a strong relative improvement of the solar cell performance, although absolute performance parameters remain low in comparison to hybrid solarmore » cells with colloidal cadmium or lead chalcogenide nanocrystals.« less
Authors:
; ; ;  [1]
  1. Institute of Physics, Energy and Semiconductor Research Laboratory, Carl von Ossietzky University of Oldenburg, 26111 Oldenburg (Germany)
Publication Date:
OSTI Identifier:
22492982
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACETIC ACID; CADMIUM; CHARGE TRANSPORT; COPPER SULFIDES; ELECTRONS; HETEROJUNCTIONS; INDIUM SULFIDES; ION EXCHANGE; LEAD; MATRIX MATERIALS; MORPHOLOGY; NANOPARTICLES; NANOSTRUCTURES; OPTIMIZATION; ORGANIC SOLAR CELLS; PHOTOVOLTAIC EFFECT; POLYMERS; THICKNESS; THREE-DIMENSIONAL CALCULATIONS; TOMOGRAPHY