Fabrication of morphology-controlled and highly-crystallized perovskite microwires for long-term stable photodetectors

Abstract

In this work, highly crystallized and lengths up to a centimeter organic-inorganic hybrid perovskite CH3NH3PbI3 (MAPbI3) microwires (MWs) have been prepared via a solution-based blade coating and slow solvent evaporation method. And a two-step growth mechanism was proposed to explain the formation and growth of the MAPbI3 MWs. Further, the as-prepared MWs were used to fabricate photodetectors and their photoresponse characteristics were tested and detailedly analyzed. The results reveal that the devices presented stable and repeatable photocurrent responses. A high on/off photocurrent ratio of 0.84 × 104, a photoresponsivity of 0.04 A/W, a specific detectivity of 0.6 × 1012 Jones, and a fast response speed of 178/173 μs were realized in the prepared MAPbI3 photodetectors. More importantly, even without encapsulation, the proposed photodetectors demonstrate remarkable operation stability, above 80% of the photocurrent has been retained after a long running time (50,000 s, 45–55% humidity). After 60 days storage without encapsulation in air ambient, the proposed photodetectors can be efficiently sustained, demonstrating a strong ability to resist the water and oxygen degradation, greatly superior to reference photodetectors constructed with MAPbI3 thin films. This work opens up an exciting opportunity for using MAPbI3 MWs for high-performance and low-cost photodetectors applications.