P‐11.3: Manufacturing Quantum Dot Pixel Array via Self‐Assembling on Hydrophobic‐Hydrophilic Transformation Substrate

Abstract

Quantum dots (QDs) have been considered next-generation display fluorescent conversion materials due to their excellent color purity and photoluminescence quantum yield. In order to integrate QD with Micro/Mini-LED and other microdevices efficiently, it is necessary to fabricate micro-scale QD pixel arrays. Photolithography is an effective method for fine pattern processing, but conventional photolithographic procedures need to compound QD with a photosensitive curing matrix, which is not conducive to obtaining high color purity QD pixels. Therefore, a QD self-assembly strategy based on a hydrophobic-hydrophilic transformation substrate is proposed, combining ultraviolet (UV) mask exposure and surface charge modification technology to manufacture a high-purity QD pixel array. In this paper, the hydrophobic-hydrophilic transformation substrate is prepared by polyvinylidene fluoride (PVDF)/TiO2 hybrid fibrous membrane substrate. By changing the thickness of the substrate and analyzing its threshold of the photocatalysis time and pattern accuracy combined with the transmittance after encapsulation, the optimal substrate thickness is about 30 um. On this basis, the surface charge of the fibrous membrane is further modified by poly(diallyldimethylammonium chloride) (PDDA) to enhance the self-assembly performance of the QD in the hydrophilic region. The dimensional accuracy and optical characteristic of the QD pixel array have been studied in detail. The color average degree is 96.4%, the consistency is 94.5%, and the dimensional accuracy error is 5.2%. The spectrum of the QD pixel is almost the same as the QD solution, and the transmittance of the films is up to 88.8% under the visible light wave band, which has excellent optical performance. Therefore, this strategy is beneficial for efficiently manufacturing the high-purity QD pixel array, which has a broad application prospect in the high-resolution display field of Micro/Mini light-emitting diodes (LEDs).