Enhanced photocurrent of self-powered ultraviolet photodetectors based on Ba1−xSrxTiO3 ceramics via ferroelectric polarization

Abstract

Research of photovoltaic energy conversion devices based on ferroelectric materials has received growing attention in recent years. However, the low photocurrent of the traditional ferroelectric ceramics is the key challenge for the development of these devices. Here, the photocurrent of the self-powered ultraviolet (UV) photodetectors based on Ba1−xSrxTiO3 (BSTO) ceramics is increased by strontium doping and ferroelectric poling. At zero bias, the BSTO/electrolyte heterojunction-based photodetectors demonstrate over 460% enhancement of photocurrent at x = 0.15 compared to that at x = 0.05. Moreover, by applying poling bias from −15 V to +15 V to the BSTO (x = 0.15) sample, the photocurrent can be tuned from 6% to 260% of that of the unpoled BSTO. The variation of energy band structure in depletion region induced by surface ferroelectric polarization is proposed to be responsible for the switchable photoelectrochemical response. This work suggests that substitutional doping of metal ions and ferroelectric polarization has great promise in increasing the photoelectrochemical properties of the ferroelectric ceramics.