Ultrahigh photovoltage responsivity of PEDOT:PSS–silicon hybrid heterojunction photodiodes

Abstract

Strong inversion at the poly(3,4-ethylenedioxythiophene): polystyrene sulfonate PEDOT:PSS/silicon interface facilitates the separation of excess carriers and obstructs surface recombination, both are of utmost importance for optoelectronic detectors. In this view, low-temperature solution-processed PEDOT:PSS/silicon hybrid heterojunctions possess great potential for light detection applications. We investigate the performance of hybrid PEDOT:PSS/silicon photodetectors following long-period exposure to ambience. In addition, the effect of PEDOT:PSS conductivity on the performance of hybrid heterojunction photodiodes is also explored. In the self-powered photovoltage mode, the hybrid photodiode displays an ultrahigh responsivity of 106 V/W, a noise equivalent power of 10 pW/Hz, and a detectivity up to 1010 Jones. Thermal noise is identified as the main limiting factor in the device performance. The hybrid photodetector demonstrates a desirable stability over long-time storage in air.