In situ current voltage measurements for optimization of a novel fullerene acceptor in bulk heterojunction photovoltaics

TitleIn situ current voltage measurements for optimization of a novel fullerene acceptor in bulk heterojunction photovoltaics
Publication TypeJournal Article
Year of Publication2012
AuthorsC.G. Shuttle, N.D. Treat, Jian Fan, Alessandro Varotto, C.J. Hawker, F. Wudl, and M.L. Chabinyc
JournalJOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS
Volume50
Pagination174-179
Date PublishedFEB 1
ISSN0887-6266
Keywordsbulk heterojunction, conducting polymers, diodes, fullerenes, photovoltaics, polymer thin films, semiconducting polymers, thin films
AbstractThe evaluation of the power conversion efficiency (PCE) of new materials for organic bulk heterojunction (BHJ) photovoltaics is difficult due to the large number of processing parameters possible. An efficient procedure to determine the optimum conditions for thermal treatment of polymer-based bulk heterojunction photovoltaic devices using in situ current-voltage measurements is presented. The performance of a new fullerene derivative, 1,9-dihydro-64,65-dihexyloxy-1,9-(methano[1,2] benzomethano)fullerene[60], in BHJ photovolatics with poly(3-hexylthiophene) (P3HT) was evaluated using this methodology. The device characteristics of BHJs obtained from the in situ method were found to be in good agreement with those from BHJs annealed using a conventional process. This fullerene has similar performance to 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methano fullerene in BHJs with P3HT after thermal annealing. For devices with thickness of 70 nm, the short circuit current was 6.24 mA/cm(2) with a fill factor of 0.53 and open circuit voltage of 0.65 V. The changes in the current-voltage measurements during thermal annealing suggest that the ordering process in P3HT dominates the improvement in power conversion efficiency. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 50: 174-179, 2012
DOI10.1002/polb.22388