A Universal High-Resolution Micro-Patterning Technique for Solution-Processed Materials

Abstract

A universal method of micro-patterning thin quantum dot films is highly desired by industryto enable integration of quantum dot(QD) materials with optoelectronic devices. Many of the methods reported so far, including specially engineered photoresist or ink-jet printing, are either of poor yield, resolution limited, difficult to scale for mass production, overly ex- pensive or sacrifice some optical quality of the quantum dots. Dry photolithographic lift-off method is a promising solution for pixelization of solution-processed materials. Recent work demonstrated patterning of perovskite quantum dot pixels, 10 µm in diameter, to construct a static micro-display. This thesis presents an advancement of this method demonstrating high-resolution patterning ( 1 µm diameter) with full-scale processing on 100 mm wafer, and multi-color integration of two different varieties of quantum dots. In this work, both perovskite and cadmium-selenide quantum dots were employed, though the method is adaptable to other solution-processed materials. Specifically, green perovskite quantum dots were synthesized using a room-temperature ligand-assisted repre- cipitation method, resulting in a photoluminescent quantum yield of 93.6% and a full-width half-maximum emission linewidth of less than 20 nm. The thesis also explores the synthesis and characterization of these QDs. These results demonstrate the viability of this method for use in scalable manufactur- ing of high-resolution micro-displays. Future work will focus on integrating UV or blue pixel sources with multi-color patterning to realize a full-color display, further pushing the boundaries of this promising technology.