Room temperature synthesis of Sn2+ doped highly luminescent CsPbBr3 quantum dots for high CRI white light-emitting diodes

Abstract

With a high photoluminescence quantum yield (PLQY) being able to exceed 90% for those prepared by the hot injection method, CsPbBr₃ quantum dots (QDs) have attracted intensive attention for white light-emitting diodes (WLEDs). However, the whole process is carried out in a 3-neck flask via air isolation and at a relatively high temperature. In addition, CsPbBr₃ QDs suffer from poor stability under ambient atmosphere. In this work, an effective strategy through doping of Sn²⁺ ions at room-temperature is proposed to improve the emission efficiency and stability of CsPbBr₃ QDs. Compared with pure CsPbBr₃ QDs, a higher PLQY and a better stability are obtained. The detailed physical mechanism for this performance enhancement is discussed and described. An optimum result is found at an Sn²⁺ doping amount of 20%, which shows a high PLQY of 82.77%. WLEDs based on these 20% Sn²⁺ doped CsPbBr₃ QDs are also studied, exhibiting a high color rendering index of 89 and a correlated color temperature (CCT) of 3954. The method proposed here provides an effective strategy to enhance the fluorescence and stability of CsPbBr₃ QDs, which might have promising potential in the lighting fields.