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A Small Molecule Non‐fullerene Electron Acceptor for Organic Solar Cells
Author(s) -
Schwenn Paul E.,
Gui Ke,
Nardes Alexandre M.,
Krueger Karsten B.,
Lee Kwan H.,
Mutkins Karyn,
RubinsteinDunlop Halina,
Shaw Paul E.,
Kopidakis Nikos,
Burn Paul L.,
Meredith Paul
Publication year - 2011
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201000024
Subject(s) - materials science , organic solar cell , fullerene , electron acceptor , acceptor , crystallinity , polymer solar cell , amorphous solid , hybrid solar cell , organic semiconductor , energy conversion efficiency , solar cell , photovoltaic system , molecule , polymer , heterojunction , chemical engineering , thin film , electron mobility , photoluminescence , nanotechnology , photochemistry , optoelectronics , organic chemistry , chemistry , ecology , physics , composite material , biology , condensed matter physics , engineering
Organic bulk heterojunction photovoltaic devices predominantly use the fullerene derivatives [C60]PCBM and [C70]PCBM as the electron accepting component. This report presents a new organic electron accepting small molecule 2‐[{7‐(9,9‐di‐ n ‐propyl‐9 H ‐fluoren‐2‐yl)benzo[ c ][1,2,5]thiadiazol‐4‐yl}methylene]malononitrile (K12) for organic solar cell applications. It can be processed by evaporation under vacuum or by solution processing to give amorphous thin films and can be annealed at a modest temperature to give films with much greater order and enhanced charge transport properties. The molecule can efficiently quench the photoluminescence of the donor polymer poly(3‐ n ‐hexylthiophene‐2,5‐diyl) (P3HT) and time resolved microwave conductivity measurements show that mobile charges are generated indicating that a truly charge separated state is formed. The power conversion efficiencies of the photovoltaic devices are found to depend strongly on the acceptor packing. Optimized K12:P3HT bulk heterojunction devices have efficiencies of 0.73±0.01% under AM1.5G simulated sunlight. The efficiencies of the devices are limited by the level of crystallinity and nanoscale morphology that was achievable in the blend with P3HT.