Near-unity blue-orange dual-emitting Mn-doped perovskite nanocrystals with metal alloying for efficient white light-emitting diodes

The enhanced blue-orange dual-emitting Mn 2+ doped CsPbCl 3-x Br x nanocrystals with near-unity photoluminescence quantum yield up to 97% were synthesized through post-treatment of CdBr 2 at room temperature due to improved efficiency of energy transfer from exciton to Mn and used to fabricate all-inorganic perovskite nanocrystal based warm white light emitting diodes with high performance. The tunable dual-color emitting Mn 2+ doped CsPbCl 3-x Br x nanocrystals (NCs) with near-unity photoluminescence quantum yield (PL QY) were synthesized through post-treatment of metal bromide at room temperature for fabrication of efficient warm white light-emitting diodes (WLEDs). Especially, the CdBr 2 treated blue-orange emitting Mn doped NCs with various Mn/Pb molar feed ratios exhibit higher PL QY of 97% and longer Mn 2+ PL lifetime of 0.9 ms. It is surprisingly found that the X-ray diffraction peak at 31.9° is almost not changed with increasing Br composition, meaning formation of metal alloying due to incorporation of amount of divalent cation in NCs. The strong and stable Mn 2+ PL at temperature ranging from 80 K to 360 K are revealed and the temperature-dependent energy transfer efficiencies in Mn 2+ doped CsPbCl 1.5 Br 1.5 NCs are obtained. The enhancement mechanism of Mn 2+ PL QY was attributed to improved energy transfer from exciton to Mn 2+ d–d transition and suppressed defect state density after post-treatment. The efficient warm WLEDs with color rendering index of 90 and luminous efficacy of 92 lm/W at 10 mA were fabricated by combining blue-orange dual-emitting Mn 2+ doped CsPbCl 3-x Br x @SiO 2 and green emissive CsPbBr 3 @SiO 2 NCs with violet GaN chips.