Patterning All‐Inorganic Halide Perovskite with Adjustable Phase for High‐Resolution Color Filter and Photodetector Arrays

Perovskite has been actively studied for optoelectronic applications, such as photodetectors and light-emitting diodes (LEDs), because of its excellent optoelectronic properties. However, ionic bonds of the perovskite structure are vulnerable to chemicals, which makes perovskite incompatible with photolithography processes that use polar solvents. Such incompatibility with photolithography hinders perovskite patterning and device integration. Here, an all-solution based cesium lead halide perovskite (CsxPbyBrz) patterning method is introduced in which PbBr2 is patterned and then synthesized into CsxPbyBrz. Each step of the top-down patterning process (e.g., developing, etching, and rinsing) is designed to be compatible with existing photolithography equipment. Structural, chemical, and optical analyses show that the PbBr2 pattern of (10 mu m)(2) squares is successfully transformed into CsPbBr3 and Cs4PbBr6 with excellent absorption and emission properties. High-resolution photoconductor arrays and luminescent pattern arrays are fabricated with CsPbBr3 and Cs4PbBr6 on various substrates, including flexible plastic films, to demonstrate their potential applications in image sensors or displays. The research provides a fundamental understanding of the properties and growth of perovskite and promotes technological advancement by preventing degradation during the photolithography process, enabling the integration of perovskite arrays into image sensors and displays.