Patterning All‐Inorganic Halide Perovskite with Adjustable Phase for High‐Resolution Color Filter and Photodetector Arrays
Woosik Kim, Su‐Kyung Kim, Sanghyun Jeon, Junhyuk Ahn, Byung Ku Jung, Sang Yeop Lee, Chanho Shin, Tae‐Yeon Seong, Sohee Jeong, Ho Seong Jang, Tse Nga Ng, Soong Ju Oh
Abstract
Abstract 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 (Cs x Pb y Br z ) patterning method is introduced in which PbBr 2 is patterned and then synthesized into Cs x Pb y Br z . 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 PbBr 2 pattern of (10 µm) 2 squares is successfully transformed into CsPbBr 3 and Cs 4 PbBr 6 with excellent absorption and emission properties. High‐resolution photoconductor arrays and luminescent pattern arrays are fabricated with CsPbBr 3 and Cs 4 PbBr 6 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.