Low dark current small molecule organic photodetectors with selective response to green light

Abstract

We report green-sensitive organic photodetectors consisting of a bulk heterojunction blend of N,N-dimethylquinacridone and dicyanovinyl-terthiophene. Devices incorporating a triphenylamine derivative-based electron blocking layer and a molybdenum oxide hole extracting layer lead to significantly low dark currents (Jd) ∼ 6.41 nA/cm2 at −3 V and high external quantum efficiency of 55.2% at 540 nm wavelength with a narrow full width at half maximum of 146 nm, which is likely to be applicable for full colour organic image sensors. Based on the interfacial energy barrier and temperature dependent current-voltage characteristics, possible origins of the reverse Jd of devices are further described.