CsPbBr₃:Na with an Adjustable Bandgap, Improved Luminescence Stability, and its Application in WLEDs with Excellent Color Quality and Vision Performance

Abstract

It is still a great challenge to obtain multicolor tunable luminescence and improve the stability of luminescence through reasonable design of materials in the field of white light-emitting diodes (WLEDs). In particular, it is more important to improve the luminescence intensity and stability of blue-emitting materials. Here, the properties of CsPbBr 3 , CsPbBr 3 :Na , and NaPbBr 3 are investigated theoretically by using density functional theory (DFT). Based on the DFT theoretical calculation results, it is assumed that unexpected performance may be achieved by replacing Cs in CsPbBr 3 with Na or passivating the surface of CsPbBr 3 with Na. As expected, the tunable luminescence from blue to green is successfully achieved from CsPbBr 3 :Na, and the stability is improved. After experimental optimization, the obtained CsPbBr 3 :Na (CPBN-4) with high luminescence stability is used as blueemitting materials to construct the WLED devices with excellent color quality (CRI 92) and correlated color temperature of 9582 K.

High-Performance In3+-Doped CsPbBr3 Quantum Dots for Wide Color Gamut Backlighting

“…Perovskite quantum dots (QDs) have achieved great attention in displays and solar cell in recent years. , In particular, CsPbBr 3 QDs are considered as promising green emitters for LCD backlighting to achieve a wide color gamut due to their narrow emission properties, − but there are still some challenges in their application, such as low stability under prolonged exposure to light or high temperature. − The poor thermal stability of QDs is due to the inability of long-chain ligands to bind tightly to the surface of QDs and detach from the surface of QDs upon heating, and in addition, heating can cause severe aggregation of QDs, both of which will quench their emission. , The poor photostability of QDs is due to the light soaking effect. , When QDs are exposed to continuous light irradiation, the surface atoms detach from the surface and form more vacancy defects, which will reduce their emission. , To improve the stability of CsPbBr 3 QDs, surface coating has been shown to be an effective way . For this strategy, CsPbBr 3 QDs are encapsulated by inorganic materials (e.g., SiO 2 and Al 2 O 3 ) − or polymers (e.g., polyethylenimine) , or MOF, which isolate CsPbBr 3 QDs from each other and from the external environment, inhibit light-induced decomposition and aggregation, and thus improve their stability .…”