Improved Synthesis of Blue InP/ZnS Quantum Dots via Dynamic Chloride Ion Capping

Quantum dot light-emitting diodes (QLEDs) offer distinct advantages for achieving precise color visualization, with eco-conscious InP-based QLEDs attracting significant attention. However, the development of blue InP QLEDs has lagged far behind that of their red and green counterparts due to the enormous challenges in achieving high-quality shell epitaxy on small-sized InP cores required for blue emission. Here, we propose a strategy for synthesizing superb blue InP/ZnS QDs by employing dynamic selective surface coverage of the InP core with chloride ions. This method delicately balances the growth kinetics of shell precursors across different crystal planes, enabling uniform shell epitaxy. The prepared blue-emitting InP/ZnS QDs exhibit markedly reduced structural defects and an upward-shifted band alignment, which enhance charge injection and particularly mitigate the common issue of insufficient hole injection in blue QLEDs. Consequently, we achieved a record external quantum efficiency of 4.1% for blue InP QLEDs.