Band-edge modulated ZnO pomegranates-on-paper photodetector

Abstract

Recently, significant progress has been achieved in paper electronics due to their potential technological applications in rollup displays, wearable devices and smart cards. However, it is still a challenge to efficiently form suitable structured materials on paper substrates due to their porous and rough surface. In this research, ZnO pomegranates composed of 8 nm ZnO nanodots, have been successively fabricated on a pencil drawn graphite-on-paper substrate by an eco-friendly and cost effective solvothermal method. Most significantly, this solution grown photoconductive photodetector shows good device performances with spectrum responsivity to ultraviolet light of 0.06 A W⁻¹ and a quick response time of 4.3 s. Systematic analysis shows that the interface-related energy boundary modulation within ZnO pomegranates may facilitate the separation of photo-induced carriers, eventually resulting in its low dark current and quick response. Meanwhile, this structure designing strategy can be utilized for the future fabrication of high performance paper electronics with other materials. Besides, due to the firm attachment of ZnO pomegranates on the substrate, caused by the introduction of ethanol during the solvothermal growth process and ultrasonic vibration during the formation of the ZnO seed layer, this device is also a highly flexible and rolled-up photodetector with good reversible characteristics and steady performance towards bending deformations and irradiation degradation.