DMSO modified PEDOT:PSS polymer/ZnO nanorods Schottky junction ultraviolet photodetector: Photoresponse, external quantum efficiency, detectivity, and responsivity augmentation using N doped graphene quantum dots

Abstract

Abstract Schottky junction ultraviolet (UV) photodetector was fabricated by spin coating a hole conducting polymer, poly 3,4-ethylenedioxythiophene: polystyrene sulfonate (PEDOT:PSS) on hydrothermally grown zinc oxide (ZnO) nanorod array. The photodetector performance was improved by increasing the conductivity of PEDOT:PSS polymer using dimethyl sulfoxide (DMSO) additive. The UV detector performance was further enhanced significantly by sensitizing ZnO nanorods with N doped graphene quantum dots (NGQDs). NGQD decorated ZnO NRs/DMSO-PEDOT:PSS Schottky junction device demonstrated superior external quantum efficiency (EQE ∼ 90063%), responsivity ( R λ ∼247 A/W) and detectivity ( D λ ∼2.42 × 1011 Hz1/2/W) at 340 nm wavelength and –1V external bias. The EQE of NGQD modified sample was 56 times higher than pristine PEDOT:PSS/ZnO NR and 4.3 times higher than DMSO modified PEDOT:PSS/ZnO NRs device. NGQD sensitized detector showed superior photocurrent of 80.77 mA/cm2 at 340 nm wavelength, –1V external bias, which was 2 times higher than DMSO modified and 32 times higher than pristine PEDOT:PSS based device. The photocurrent rise and decay time of NGQD sensitized NRs are very fast compared to other photodetectors.