In-situ photo-patternable ZnO via dual-functional surface engineering strategy for high-resolution QLED devices

In-situ photo-patterning of ZnO was successfully achieved at room temperature. • QLEDs utilizing photolithographic ZnO as the ETL demonstrated superior performance. • The positive-aging effect was significantly alleviated by using photolithographic ZnO. • ZnO patterns were utilized to construct carrier transport channels in pixelated QLEDs. Benefiting from the adjustable emission spectrum, high color purity, wide gamut, and solution-processability, quantum dot light-emitting diode (QLED) is considered one of the most promising next-generation display technologies. As a prevalent electron transport material, ZnO plays a crucial role in enhancing the efficiency and long-term stability of QLED devices. To promote the development of high-resolution QLED displays, this study proposes a dual-functional surface engineering strategy for achieving in-situ photo-patternable ZnO with enhanced electrical properties. Physicochemical characterization revealed that surface defects of ZnO were significantly reduced via direct photolithography, thereby decreasing non-radiative exciton recombination at the QD/ZnO interface. Particularly, the red QLED devices based on photolithographic ZnO exhibited remarkable performance, achieving a peak external quantum efficiency (EQE) of 23.5%, a brightness of over 140,000 cd m −2 at 5 V, and an alleviated positive-aging effect (i.e., anomalous brightness increase). Concurrently, the operational lifetime T 95 (the time for the device luminance to drop to 95%) was also improved from 1,036 h to 2,084 h. Furthermore, by modulating the morphology of ZnO films, we successfully fabricated pixelated QLED devices, laying the technical foundation for commercializing high-resolution QLED displays. Download: Download high-res image (394KB) Download: Download full-size image