14.5: Perovskite Quantum Dot Color Conversion Pattern Fabricated by an In‐situ Inkjet Printing

Abstract

Inkjet printing technology has broad application prospects in the manufacture of optoelectronic devices due to its advantages of mask‐free and high material utilization. However, the coffee ring effect during printing can make the morphology non‐uniform and has not been thoroughly explored. In this work, we used a high‐precision in‐situ inkjet printing system to print low‐viscosity perovskite precursor inks on substrates to generate color‐converting films. The viscosity of the perovskite precursor solution was improved by changing the ratio of the 5‐AVABr additive, coupled with the choice of DMF with a higher boiling point as the solvent, which greatly reduced the evaporation of the solvent at the edge of the droplet, driving the formation of Marangoni flow which can result a uniform surface of droplets, culminating in a microarray of coffee‐free rings. Notably, the perovskite can be crystallized in situ during printing without additional annealing, relying on a pumping system to assist the solvent evaporation. With the additive, the photoluminescence quantum yield of the film increased to 39%. The size of each pixel in microarrays was controlled to be less than 60 μm and 400 pixels per inch (PPI) is realized. Our work paves the way for large‐area, high‐efficiency production of perovskite color conversion films.