materials because of their high color purity, large-scale solution processability, and tunable electrical and optical properties. [1][2][3] The InP-based QDs have been synthesized with near-unity photoluminescence quantum yield (PL QY), which can meet the RoHS requirements by removing toxic Cd from QD emitters. [4,5] Despite recent advances in QD light-emitting diodes (QD-LEDs), including a 20% external quantum efficiency and enhanced device lifetime, [4,[6][7][8][9][10][11] multicolored and pixelated QD-LED devices still need to be developed. [12] The QDs are typically synthesized using wet chemistry, which is useful for large-scale solution processes. When QDs are incorporated into a device structure and sandwiched into a multilayered thin film, solvent orthogonality should be considered because the pre-coated QD layer can be damaged by the solvent in the top layers. This can be a serious issue when the QD film is patterned as a pixelated display, where conventional photolithography cannot be used. [13,14] When photoresists are coated on top of the pre-existing QD film, the QD film is easily removed, or the two layers intermix. This is because QDs are easily dissolved or washed with organic solvents, which are also used to dissolve the photoresist. Thus, alternative patterning methods, such as inkjet [15][16][17][18][19] and transfer printing, [20][21][22] have been employed to form multicolor QD patterns. However, inkjet printing has a limited tact time and suffers from nozzle clogging issues for industrial applications. [15,23] In addition, transfer printing can yield high-resolution patterns, but the process requires precise control of kinetic parameters, such as pick-up and peeling speed, which limits the reproducibility of the process. [21,22] Therefore, it is highly desirable to use conventional photolithography for patterning QD films. [24] Two methods have been suggested for employing photolithography to QD film patterning. One is the addition of light-sensitive cross-linking molecules to the QD solution. The molecule can either replace the original ligands or can be included as an additional substance. [25][26][27] Upon light exposure, the molecules form a crosslinked structure between the QDs, and the patterns can be formed by solvent dipping. The other method directly uses a conventional photoresist because it is a well-designed chemical that provides high resolution and etch-resistance. Owing to the absence of solvent resistance in QD films, the lift-off method Colloidal quantum dot-based light-emitting diodes (QD-LEDs) are one of the potential future self-emissive displays owing to their large-scale solutionprocessibility and high color purity. For the industrial application of QD-LEDs, high-performance QD-LED and high-resolution patterning of quantum dot (QD) films are required. Photolithography is an ideal tool for patterning QD films. Previously, the high-resolution patterning of QD films using direct photolithography by ultra-thin atomic layer deposition of ZnO on the QD surface is reported. Th...
