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Effect of trichlorobenzene additive on the performance and morphology of polyfluorene and fullerene derivative bulk heterojunction solar cells
Author(s)
Date Issued
August 1, 2012
Type
Article
Abstract
The influence of additive, namely 1,3,5-trichlorobenzene (TCB), on the morphology and performance of bulk heterojunction (BHJ) organic solar cells was studied based on a 1:2 (w/w) blend of benzothiadiazole/thiophene-based copolymers (PFTBzTT) to [6,6]-phenyl-C 61 butyric acid methyl ester (PCBM). The active layers were deposited by spin-coating from solutions using chloroform, with different additive concentrations from 0 to 36mg/ml. The addition of solvent additive into the polymer solution was able to improve the performance of BHJ solar cells. The maximum power conversion efficiency (%PCE) of 0.85% was obtained for a cell with the TCB concentration of 12mg/ml after annealing at 180°C for 20min. From atomic force microscopy (AFM) images, the films processed without TCB appear smoother than those with the TCB additive. A large extent of segregation was also observed in the films processed with a high TCB concentration. The optical images of the thin films suggest that the optimum concentrations of the additive cause the polymer self-organisation, resulting in some aggregation of large PCBM crystals. © 2011 Canadian Society for Chemical Engineering.
Citation
Canadian Journal of Chemical Engineering, 90(4), 897-902, 2012