Controllable Vapor-Phase Growth of Inorganic Perovskite Microwire Networks for High-Efficiency and Temperature-Stable Photodetectors

Recently, metal halide perovskites have attracted tremendous research interest due to their exceptional optoelectronic properties, showing great application potentials in the fields of solar cells, light-emitting diodes, and photodetectors. However, most of the previously reported perovskite photodetectors are based on the polycrystalline perovskite films, and the amounts of defects and large grain boundaries in the films are unfavorable for further improvement of the performance of the device. In this study, high-quality CsPbCl₃ microwire networks (MWNs) were successfully prepared by a vapor-phase method. By changing the evaporation temperature of source powders, a series of MWs with different widths and coverage can be obtained. Ag electrodes were thermally deposited onto the surface of the mica substrate through a shadow mask, and symmetrically structured photoconductive detectors were fabricated. The performance of the studied photodetector is remarkable in terms of its high on/off photocurrent ratio of 2.0 × 10³, a photoresponsivity of 14.3 mA/W, and a fast response speed of 3.212/2.511 ms. It is worth noting that the fast varying optical signal can be detected, even at a high frequency of 3500 Hz. More importantly, the proposed CsPbCl₃ MWN photodetectors without encapsulation demonstrate a remarkable operation stability over the test in air ambient, can withstand a high working temperature of 373 K for 9 h continuous operation, and nearly 70% of the original photocurrent of the photodetectors has been retained, further confirming the ultrastable device operation. Note that this is the first report on high-temperature operation behaviors of perovskite photodetectors. The results in this study may promote the development of stable and high-efficiency perovskites photodetectors compatibility for practical applications under harsh conditions.