Effect of solvents on the performance and morphology of polymer photovoltaic devices

Abstract

In the polymer photovoltaic devices (PVDs), the performance of devices was strongly influenced by region-regularity, number average molecular weight and casting solvents of polymers. In this work, we fabricated p-n bulk-hetero-junction PVDs based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C-60-butyric acid methyl ester (PCBM) using various solvents such as chloroform (CF), chlorobenzene (CB), dichlorobenzene (DCB), and mixed solvent (CF/CB, CF/DCB). Thin film of active layer with P3HT/PCBM was prepared by spin coating and thermal annealing at 150 degrees C with fixed thickness about 110 nm by adjusting solution concentration. The crystalline morphology and layered phase for the active layer were studied by atomic force microscopy and X-ray diffraction, respectively. We investigated the performance of solar cells according to different morphology and crystallinity of active layer by various solvent and mixed solvent. (C) 2009 Published by Elsevier B.V.