Double perovskite Cs2NaInCl6 nanocrystals with intense dual-emission via self-trapped exciton-to-Tb3+ dopant energy transfer

Lead-free double perovskite (DP) nanocrystals (NCs) with low-toxicity and good stability have attracted attention for light-emitting device (LED) applications. However, low photoluminescence quantum yields (PLQYs) limit their development. Here, we synthesized Tb3+,Sb3+ co-doped Cs2NaInCl6 NCs using an improved hot-injection method. The as-prepared Cs2NaInCl6:Sb,Tb NCs exhibit dual-emission from self-trapped excitons (STEs) to Tb3+ ions. The maximum PLQY of Cs2NaInCl6:Sb,Tb NCs is 74%, which exceeds that of most lead-free DP NCs. The energy transfer channel from STEs to Tb3+ ions in Tb3+,Sb3+ co-doped Cs2NaInCl6 NCs has been proved and studied. In addition, we further introduce Mn2+ ions and fabricate the corresponding warm white light-emitting diodes (WLEDs). This work provides a reliable way to realize DP NCs with enhanced photoluminescence properties and further promoted their development for WLED applications.