Highly efficient red emission of CsPbBrI2 quantum dots glasses modified by Nb5+ for light-emitting application

Abstract

Red-emitting perovskite quantum dots (QDs) have significant potential for application in optoelectronic devices. However, their application is hindered by preparation challenges and low photoluminescence quantum yield (PLQY). In this study, CsPbBrI2 red-emitting QDs with a PLQY of up to 58.73 % were synthesized in germanium borate glass. The experimental results indicated that the addition of Nb5+ can not only partially replace the Pb2+ sites but also passivate halogen defects in QDs, enhance radiative transitions, and significantly improve the lattice ordering of CsPbBrI2 QDs glass. Additionally, the incorporation of Nb2O5 supplies free oxygen, facilitating the conversion of [BO4] to [BO3] in the glass network, which results in a looser structure conducive to crystallization. Moreover, the Nb5+-doped CsPbBrI2 QDs glass demonstrated excellent hydrothermal stability. The QDs glass exhibiting the highest luminescent performance was subsequently combined with an InGaN blue chip to create a WLED with a color rendering index (CRI) of 82.7. This study offers an innovative methodology for synthesizing perovskite QDs glass materials with enhanced red emission efficiency through transition metal doping, highlighting their significant potential for practical applications in WLEDs.