Processing additives for improved efficiency from bulk heterojunction solar cells.
Two criteria for processing additives introduced to control the morphology of bulk heterojunction (BHJ) materials for use in solar cells have been identified: (i) selective (differential) solubility of the fullerene component and (ii) higher boiling point than the host solvent. Using these criteria, we have investigated the class of 1,8-di(R)octanes with various functional groups (R) as processing additives for BHJ solar cells. Control of the BHJ morphology by selective solubility of the fullerene component is demonstrated using these high boiling point processing additives. The best results are obtained with R = Iodine (I). Using 1,8-diiodooctane as the processing additive, the efficiency of the BHJ solar cells was improved from 3.4% (for the reference device) to 5.1%.
Lee
Jae Kwan
JK
Center for Polymers and Organic Solids, University of California at Santa Barbara, Santa Barbara, California 93106, USA.
Ma
Wan Li
WL
Brabec
Christoph J
CJ
Yuen
Jonathan
J
Moon
Ji Sun
JS
Kim
Jin Young
JY
Lee
Kwanghee
K
Bazan
Guillermo C
GC
Heeger
Alan J
AJ