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

Abstract

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 (JSC) of 1.32 mA cm−2, an open circuit voltage (VOC) 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 °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 VOC (up to 0.71 V) in photovoltaic device.