Use of Organic Polymer P3HT:PC61BM as the Active Layer to Improve the Performance of ZnO Ultraviolet Photodetector

One of the most interesting structures of organic photodetectors (OPDs) is the bulk heterojunction (BHJ), which can be achieved by mixing electron donors and electron acceptors in a suitable solvent and then spin-coating. BHJs have proven to be a very useful method to overcome the short diffusion length of organic semiconductor excitons. However, this structure enhances disorder and hinders the collection of photogenerated carriers. Therefore, it is very important to prepare OPDs with this structure. In this paper, we show how to use conjugate polymer donor poly(3-hexylthiophene) (P3HT) and fullerene derivative acceptor 6,6-phenyl C61-butyric acid methyl ester (PC61BM) to form a binary BHJ active layer by spin-coating to improve the performance and detector wavelength of a ZnO ultraviolet (UV) photodetector (PD). Compared with the ZnO UV PD, the responsivity of the OPD can reach 0.58 A W–1, which is increased by about 7.14 times. Furthermore, the OPD shows improved absorption, high photocurrent to dark current ratio (1.63 × 104), and excellent detection capability (3.67 × 1012 Jones). The preparation of a new OPD by this work shows strong performance and provides a new idea for the research of OPD. Therefore, it is very important to design and manufacture ZnO UV PD to form a BHJ OPD with organic polymers P3HT:PC61BM.