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Fabricating High Performance, Donor–Acceptor Copolymer Solar Cells by Spray‐Coating in Air
Author(s) -
Wang Tao,
Scarratt Nicholas W.,
Yi Hunan,
Dunbar Alan D. F.,
Pearson Andrew J.,
Watters Darren C.,
Glen Tom S.,
Brook Andrew C.,
Kingsley James,
Buckley Alastair R.,
Skoda Maximilian W. A.,
Donald Athene M.,
Jones Richard A. L.,
Iraqi Ahmed,
Lidzey David G.
Publication year - 2013
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.201200713
Subject(s) - materials science , pedot:pss , acceptor , chemical engineering , polymer solar cell , energy conversion efficiency , spin coating , organic solar cell , hybrid solar cell , coating , layer (electronics) , copolymer , photoactive layer , polymer , active layer , fabrication , carbazole , cathode , photovoltaic system , solar cell , optoelectronics , nanotechnology , composite material , organic chemistry , thin film transistor , ecology , chemistry , engineering , biology , condensed matter physics , physics , alternative medicine , pathology , medicine
We report the fabrication of high performance organic solar cells by spray‐coating the photoactive layer in air. The photovoltaic blends consist of a blend of carbazole and benzothiadiazole based donor–acceptor copolymers and the fullerene derivative PC 70 BM. Here, we formulate a number of photovoltaic inks using a range of solvent systems that we show can all be deposited by spray casting. We use a range of techniques to characterize the structure of such films, and show that spray‐cast films have comparable surface roughness to spin‐cast films and that vertical stratification that occurs during film drying reduces the concentration of PCBM towards the underlying PEDOT:PSS interface. We also show that the active layer thickness and the drying kinetics can be tuned through control of the substrate temperature. High power conversion efficiencies of 4.3%, 4.5% and 4.6% were obtained for solar cells made from a blend of PC 70 BM with the carbazole‐based co‐polymers PCDTBT, P2 and P1. By applying a low temperature anneal after the deposition of the cathode, the efficiency of spray‐cast solar‐cells based on a P2:PC 70 BM blend is increased to 5.0%. Spray coating holds significant promise as a technique capable of fabricating large‐area, high performance organic solar cells in air.