A Hole Transport Layer-Free, More Thermally Stable, Self-Powered CH_3NH_3PbBr_3-Based Multiband Imaging Photodetector with Novel Topological Insulator Bi_2Te_3 Electrodes

摘要

The conventional forward-structure perovskite devices typically employ organic small molecule and noble metal as the hole transport layer (HTL) and electrode, respectively, which results in poor thermal stability and high costs. To address this issue, a HTL-free CH_3NH_3PbBr_3 photodetector with the topological insulator bismuth telluride (Bi_2Te_3) electrode is developed. The device exhibits apparent sensitivity to ultraviolet/visible waveband with a peak responsivity of 97.5 mA W~(?1), switching ratio exceeding 10~4, and the detectivity is up to 10~(12) Jones without external bias. These figures-of-merit are distinguished among the reported CH_3NH_3PbBr_3-based devices. Impressively, this device presents a light power-modulated near-infrared detection thanks to the contribution of topological insulator Bi_2Te_3, and the underlying mechanism is elaborated in-depth. Moreover, the novel device improves significantly in short and long-time thermal stability. Benefiting from these distinguished properties, the photodetector is imaging-capable and a 50 × 50 pixels’ pattern with satisfactory resolution has been achieved. This work highlights the application of topological insulators on the HTL-free perovskite photodetector, offering new insights for the future commercialization of perovskite devices.