Direct Optical Patterning of Quantum Dot Light-Emitting Diodes Based on Ultrafast, Low-Energy, Site-Controlled Click Chemistry Reaction

As one of the most promising next-generation display technologies, quantum dot light-emitting diodes (QLEDs) possess various advantages, such as high color purity, wide color gamut, high brightness, and solution processability. The preparation of quantum dot (QD) pixels is essential for commercializing QLED displays, and direct photolithography is considered an efficient method for fabricating ultra-high-resolution devices over large areas. However, the QD direct photolithography technology is still in its infancy. This study presents a novel direct photolithography technique based on a typical azide-alkyne click reaction. This method enables the cross-linking of adjacent QDs in an air environment using a 365 nm UV light source, and a low-energy dose (≈36 mJ cm −2 ). In addition, the QLEDs with crosslinked QD layers exhibit excellent performance, achieving a peak external quantum efficiency (EQE) of 20.05% and a maximum brightness over 166,000 cd m −2 at 5 V. Meanwhile, the QLEDs with pristine and photolithographic QDs exhibit comparable operational lifetime (T 95 ). It is believed that the novel direct photolithography technology based on azide-alkyne click reaction will advance the development of patterned QDs and facilitate the industrial production of ultra-high resolution QLED displays.