Simultaneous Synthesis, Modification, and DFT Calculation of Three‐Color Lead Halide Perovskite Phosphors for Improving Stability and Luminous Efficiency of WLEDs

Abstract

The all‐inorganic metal halide perovskite CsPbX3 (X = Cl, Br, and I) has received extensive attention in the field of white light‐emitting diodes (WLEDs) due to its high luminous intensity and high color purity. However, the shortcoming of poor stability directly affects the luminous performance of the WLED devices and reduces their luminous efficiency, which has become an urgent problem to be solved. Here, three‐color lead halide perovskite phosphors (blue‐emitting CsPbBr3 synthesized at 20 °C (CPB‐20), green‐emitting CsPbBr3‐80 (CPB‐80)/CsPbBr3:SCN−(CPB:SCN−), and red‐emitting PEA2PbBr4 (PPB)/PEA2PbBr4:Mn2+ (PPB:Mn2+)) with higher stability and luminous intensity are simultaneously prepared and applied in WLEDs. Density functional theory is used to optimize the structures of CsPbBr3 and PEA2PbBr4, and to calculate the work function, optical properties, and charge density difference. Not only the WLED devices with three‐color lead halide perovskite phosphors are constructed, but also WLED devices from warm white to cold white are realized by tuning the ratio of the different emissions, and a superior color quality (color rendering index of 96) and ideal correlated color temperature (CCT of 9376 K) are achieved. This work will set the stage for exploring low‐cost, environmentally friendly, high‐performance WLEDs.

Manganese halide hybrids with a reversible luminous color and their application for a white light-emitting diode

“…Benefiting from flexible structural tunability, organic–inorganic lead halide hybrids possess a high charge injection capacity, long carrier diffusion length, adjustable band gap, etc. 1–7 For the past few years, lead halide hybrids have been promising candidates in the field of solar cells, photodetectors, fluorescent sensors, light-emitting diodes (LEDs) and other optoelectronic devices. 8–13 However, the harmfulness of the element Pb to the environment and instability of lead halide hybrids greatly impede their practical applications.…”

Recent Progress and Prospects on Metal Halide Perovskite Nanocrystals as Color Converters in the Fabrication of White Light-Emitting Diodes

“…A WLED device was fabricated using the CsPbBr 3 /Nd 3+ NCs integrated with an ultraviolet (UV) LED chip, producing a cool white light emission with a CIE value at (0.32, 0.34). Furthermore, Sun et al performed the synthesis of three-color perovskite phosphors, i.e., blue-emitting CsPbBr 3 NCs synthesized at 20 °C, green-emitting CsPbBr 3 NCs synthesized at 80 °C, and red-emitting Mn-doped PEA 2 PbBr 4 NCs were coupled together to generate warm white light emission with a CRI value of 96 (Sun et al, 2022).…”

Evolution and Mechanism of Cesium Lead Bromide Nanostructures in Oleylamine‐Rich System by Hot‐Injection Method

“…The inorganic halide perovskite nanostructures (CsPbBr 3 ) [1][2][3] have been extensively studied due to their excellent performance [4,5] such Besides, high stability and high PLQY CsPbBr 3 nanowires are obtained. The obtained CsPbBr 3 nanowires are applied as a green light-emitting component in white light-emitting diode (WLED) devices, which emits stable, high-intensity white light.…”