Synthesis of Chlorinated TiO2 Nanocrystals and Their Application in Quantum Dot Light Emitting Diodes

Abstract

To further improve the efficiency and stability of quantum dot light-emitting diodes (QLEDs), it is essential to explore electron transport layers (ETLs) with superior properties. Metal oxide nanocrystals, featuring wide bandgaps, suitable energy level alignment and low cost, have been widely used as ETLs in QLEDs. In this study, we prepared oleic acid-capped TiO2 nanocrystals with a narrow size distribution and high crystallinity. To enhance the charge transport capability of the TiO2 ETL, these nanocrystals were chlorinated using thionyl chloride (SOCl2 ), yielding alcoholdispersible TiO2 nanocrystals with good colloidal stability. Furthermore, a widebandgap CaMoO4 interfacial layer was introduced between the ETL and the quantum dot emissive layer to suppress exciton quenching. Consequently, the optimized TiO2 based QLEDs achieved a maximum external quantum efficiency of 11.38%, a peak luminance of 100,920 cd m -2 and a current efficiency of 17.12 cd A -1 . This work provides a new strategy for the development of high-performance TiO2 -based QLEDs.