Universal and Nondestructive Direct Photolithography of Colloidal Quantum Dots Using Photocrosslinkable Polymer Blends

Abstract There has been considerable progress in colloidal quantum dot light‐emitting diodes (QD‐LEDs) for display applications. However, their commercialization remains challenging, because of the difficulty in achieving high‐resolution, full‐color patterning of quantum dots (QDs) without degrading their optical properties. Direct photolithography has attracted attention, but it often requires complicated ligand‐exchange processes and causes ultraviolet (UV)‐induced QD degradation. Herein, a nondestructive, universal QD patterning method that blends QDs with a photocrosslinkable hole‐transport layer (HTL) polymer, poly(9‐vinylcarbazole), is presented. Upon UV irradiation, the resulting blended films form a robust crosslinked network that encapsulates and protects the QDs, enabling high‐resolution patterning while preserving their optical properties. By employing this strategy to cadmium (Cd)‐based QDs, monochrome resolutions exceeding 10 000 pixels per inch are achieved, without requiring ligand‐exchange steps. Furthermore, incorporating this photocrosslinked blended emissive layer into QD‐LEDs enhances the device performance by suppressing excess electron injection and improving hole injection, leading to a 1.7 fold increase in the external quantum efficiency and a three fold extension of operational lifetimes. Notably, this process can be readily applied to diverse QDs, including Cd‐free variants and other functional nanocrystals, highlighting the broad applicability and commercial potential of this photocrosslinkable QD‐HTL platform for next‐generation display technologies.