Direct Photo-Patterning of Efficient and Stable Quantum Dot Light-Emitting Diodes via Light-Triggered, Carbocation-Enabled Ligand Stripping
Zhong Fu, Likuan Zhou, Yue Yin, Kangkang Weng, Fu Li, Shaoyong Lu, Dan Liu, Wenyong Liu, Longjia Wu, Yixing Yang, Haifang Li, Lian Duan, Hai Xiao, Hao Zhang, Jinghong Li
Abstract
Next generation displays based on quantum dot light-emitting diodes (QLEDs) require robust patterning methods for quantum dot layers. However, existing patterning methods mostly yield QLEDs with performance far inferior to the state-of-the-art individual devices. Here, we report a light-triggered, carbocation-enabled ligand stripping (CELS) approach to pattern QLEDs with high efficiency and stability. During CELS, photogenerated carbocations from triphenylmethyl chlorides remove native ligands of quantum dots, thereby producing patterns at microscale precision. Chloride anions passivate surface defects and endow patterned quantum dots with preserved photoluminescent quantum yields. It works for both cadmium-based and heavy-metal-free quantum dots. CELS-patterned QLEDs show remarkable external quantum efficiencies (19.1%, 17.5%, 12.0% for red, green, blue, respectively) and a long operation lifetime ( T 95 at 1000 nits up to 8700 h). Both are among the highest for patterned QLEDs and approach the records for nonpatterned devices, which makes CELS promising for building high-performance QLED displays and related integrated devices.