The effect of active layer thickness on P3HT:PCBM nanoparticulate organic photovoltaic device performance

The effect of active layer thickness on the performance of nanoparticulate organic photovoltaic (NP-OPV) devices based on Poly (3-hexylthiophene) (P3HT) as electron donor and 6,6-phenyl C61 butyric acid methyl ester (PC61BM) as electron acceptor is reported. Power conversion efficiency (PCE) is observed to peak for active layer thickness of around 100 nm, which is very similar to that obtained for bulk heterojunction devices. Increasing the thickness of the active layer beyond of 100 nm decreases the short circuit current, lowering PCE. Decrease in short circuit current and hence device efficiency of NP-OPV devices is due to the serial resistance of the device increase.