In this paper we demonstrate the use of self-assembled monolayer modified indium tin oxide (ITO) electrode in bulk heterojunction solar cell structure based on a photoactive layer of poly(3-hexylthiophene) and [6,61-phenyl C61 butyric acid methyl ester (P3HT:PC61BM). The device studies show that there is a significant enhancement in the short-circuit current as well as in the shunt resistance on use of the hexamethyldisilazane (HMDS) layer. The enhancement in short-circuit current density is attributed to the good contact formed between the organic materials and the methyl groups of HMDS. A significant improvement in the external quantum efficiency is also observed in case of the HMDS modified ITO based solar cells. (c) 2014 Elsevier B.V. All rights reserved.