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Formation of Well‐Ordered Heterojunctions in Polymer:PCBM Photovoltaic Devices
Author(s) -
He Ximin,
Gao Feng,
Tu Guoli,
Hasko David G.,
Hüttner Sven,
Greenham Neil C.,
Steiner Ullrich,
Friend Richard H.,
Huck Wilhelm T. S.
Publication year - 2011
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201000573
Subject(s) - materials science , polymer , heterojunction , photovoltaic system , nanoscopic scale , annealing (glass) , polymer solar cell , spin coating , active layer , nanotechnology , exciton , thin film , optoelectronics , layer (electronics) , composite material , ecology , thin film transistor , physics , quantum mechanics , biology
The nanoscale morphology in polymer:PCBM based photovoltaic devices is a major contributor to overall device performance. The disordered nature of the phase‐separated structure, in combination with the small length scales involved and the inherent difficulty of reproducing the exact morphologies when spin‐coating and annealing thin blend films, have greatly hampered the development of a detailed understanding of how morphology impacts photovoltaic device functioning. In this paper we demonstrate a double nanoimprinting process that allows the formation of nanostructured polymer:PCBM heterojunctions of composition and morphology that can be selected independently. We fabricated photovoltaic (PV) devices with extremely high densities (10 14 mm −2 ) of interpenetrating nanoscale columnar features (as small as 25 nm; at or below the exciton diffusion length) in the active layer. By comparing device results of different feature sizes and two different polymer:PCBM combinations, we demonstrate how double imprinting can be a powerful tool to systematically study different parameters in polymer photovoltaic devices.