High‐Performance Polymer Photodetectors using ZnO Nanocrystal Trap States

Abstract

A metal oxide interfacial layer is introduced into polymer photodetectors (PPDs) to achieve low dark current and high photocurrent. Although the defects of the metal oxide play a key role in device operation, defect effects on PPDs are poorly understood. Herein, PPDs using nanoparticle (NP) and amorphous zinc oxide (ZnO) films as the indium tin oxide (ITO) modification layer are realized and characterized, and the former device shows high performance in every figure of merit: external quantum efficiency of 1980%, detectivity of 1.03×1014 Jones, responsivity of 9.51 A W−1, response time of ≈10 μs, and linear dynamic range of over 100 dB at a low reverse bias. The comparison of the NP ZnO and amorphous ZnO‐based devices and the ultraviolet (UV) light illumination effect on the devices imply the underlying operation mechanism. The surface defects in the ZnO NPs efficiently block external charge injection, whereas the defect‐induced photogenerated charge accumulation at the interface between the ZnO layer and the active layer leads to a tunneling current under illumination. This methodology provides universal guidance for fabricating high‐performance PPDs based on a metal oxide interfacial layer.