Effects of functional groups at perylene diimide derivatives on organic photovoltaic device application

Four soluble perylene diimide derivatives (PDIs) have been prepared and their UV-visible and photoluminescence (PL) spectroscopy, cyclic voltammetry (CV) and thermal properties were studied. ITO/PEDOT:PSS/poly(3-hexylthiophene) (P3HT):PDIs/LiF/Al photovoltaic devices were fabricated with PDIs as electron accepting and transporting materials. The highest incident photon-to-current conversion efficiency (IPCE) of 19% at 495 nm and the power conversion efficiency (PCE) of 0.18% under AM 1.5 (100 mW cm(-2)) with a short-circuit current density (J(SC)) of 1.32 mA cm(-2), an open circuit voltage (V-OC) of 0.36 V, and a fill factor (FF) of 0.38 have been achieved with 1 : 4 ratio of P3HT : N,N'-di(1-nonadecyl)perylene-3,4,9,10-bis(dicarboximide) (PDI-C9) after annealing at 80 degrees C for 1 h. 1,7-Bis(N-pyrrolidinyl)-N,N'-dicyclohexyl-3,4,9,10-perylenebis(dicarboximide) (5-PDI), which has the electron donating pyrrolidinyl group, absorbed the long wavelength region to give IPCE onset higher than 750 nm and the pyrrolidinyl group also raised the LUMO level of 5-PDI to render the high V-OC (up to 0.71 V) in photovoltaic device.