Triangular Micro-Grating via Femtosecond Laser Direct Writing toward High-Performance Polarization-Sensitive Perovskite Photodetectors

摘要

Thanks to attractive properties, such as defect tolerance, broad bandgaptunability, high quantum yields, and large absorption coefficient, perovskiteshave emerged as a star material in the past decade. Meanwhile, optical nano/microstructures made of perovskites offer a facile and efficient strategyto improve light-harvesting performance and sensitivity of polarization.However, there is no low-cost, high-accuracy, and reproducibility techniquefor large-scale fabrication of perovskite nano/microstructures. Here, femtosecondlaser direct writing technique is introduced to fabricate FAPbI_3perovskite micro-grating. Based on precise spatial and power control offemtosecond laser, micro-grating with different structure parameters (periodand depth) can be processed and investigated. Triangular micro-grating ofperovskite exhibits excellent emission properties (up to 67 times enhancement)owing to low reflectance and high absorption intensity. Strikingly, theoutstanding performance of perovskite triangle grating photodetectors isobtained. The responsivity and detectivity reach 11.7 A W~(?1) and 7.8 × 10~(12)Jones, which are ≈3 and 12 times larger than the control devices; they alsoexhibit lower noise and decent polarization sensitivity. Taking the advantagesof low cost, high accuracy, and reproducibility, the femtosecond laser directwriting technique endows perovskite materials with micro-photonic conceptand remarkably enhances the devices’ performance.