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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 CsPbBr₃synthesized 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 CsPbBr₃and 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. 

Abstract The effect of rare earth (RE) single atoms on photocatalytic activity is very complex due to its special electronic configuration, which leads to few reports on the RE single atoms. Here, Dy³⁺single atom composite photocatalysts are successfully constructed based on both the special role of Dy³⁺and the special advantages of CdS/g‐C₃N₄heterojunction in the field of photocatalysis. The results show that an efficient way of electron transfer is provided to promote charge separation, and the dual functions of CO₂molecular activation of rare‐earth single atom and 4flevels as electron transport bridge are fully exploited. It is exciting that under visible‐light irradiation, the catalytic performance of CdS:Dy³⁺/g‐C₃N₄is≈6.9 times higher than that of pure g‐C₃N₄. The catalytic performance of CdS:Dy³⁺and CdS:Dy³⁺/g‐C₃N₄are≈7 and≈13.7 times higher than those of pure CdS, respectively. Besides, not all RE ions are suitable for charge transfer bridges, which is not only related to the 4flevels of RE ions but also related to the bandgap structure of CdS and g‐C₃N₄. The pattern of combining single‐atom catalysis and heterojunction opens up new methods for enhancing photocatalytic activity.