Processing additives are widely used to increase the efficiency of solution processed organic solar cells. We use the Hansen solubility parameters (HSPs) to investigate novel processing additives. The HSPs predict pyrrolidinone derivatives to be efficient processing additives for OSC systems based on poly(3-hexylthiophene)/[6,6]-phenyl-C61- butyric acid methyl ester (P3HT/PCBM). Two pyrrolidinone derivatives are identified: 1-methyl-2-pyrrolidinone and 1- benzyl-2-pyrrolidinone. The processing additives are introduced with various concentrations in the formulation of P3HT and PCBM solution. The electrical characterizations show that the two processing additives significantly increase the short circuit current and thus the power conversion efficiency of the OSCs. The results thus highlight HSPs as an effective and relatively straightforward tool that can be employed to optimize OSC morphology from a theoretical standpoint. Such a tool will be invaluable for identifying additives for novel high efficiency polymer species as they are synthesized, and thus to streamline the device fabrication and device optimization process.

Date Published: 6 October 2014
PDF: 8 pages
Proc. SPIE 9184, Organic Photovoltaics XV, 91841V (6 October 2014); doi: 10.1117/12.2061381

Published in SPIE Proceedings Vol. 9184:
Organic Photovoltaics XV
Zakya H. Kafafi; Paul A. Lane; Ifor D. W. Samuel, Editor(s)