Efficient mini/micro-perovskite light-emitting diodes

Summary: Mini- and micro-light-emitting diodes (mini/micro-LEDs) are an ideal technology platform for display and bioelectronic applications. For mini/micro-LEDs based on III-V semiconductors, the requirements for high-quality epitaxy and mass transfer are demanding, raising barriers for production yields and costs. Perovskite LEDs (PeLEDs) are an emerging alternative to conventional LEDs. However, the options for creating non-epitaxial mini/micro-LEDs by miniaturizing the pixel areas of PeLEDs are limited. Here, we demonstrate efficient single-pixel PeLEDs with active areas from 500 × 200 μm2 to 100 × 200 μm2, showing external quantum efficiencies of up to 9.1%. Key to this demonstration is 2-fold. First, a nanometer-thin lithium fluoride (LiF) interlayer allows surface tension relief within the microscopic device structure, enabling robust integration of high-efficiency PeLED architectures with self-aligned photolithography. Second, preparing uniform and highly luminescent perovskite layers are critical as the active area enters the micrometer regime. Our work paves the way toward next-generation micro-PeLED applications