Inorganic lead halide perovskite quantum dots (QDs) CsPbX3 (X = Cl, Br, or I) with superior optical and electronic properties are regarded as excellent materials for various optoelectronic devices. However, their instability significantly hinders their practical applications. Herein, composite films of CsPbBr3 QDs and polyimide (CsPbBr3@PI) are prepared using an in situ green synthesis method without other ligands and anti‐solvents. This strategy allows the formation of CsPbBr3 QDs and polymerization of polyimide monomers to occur simultaneously, which encapsulates the CsPbBr3 QDs with a protective PI layer. The CsPbBr3@PI film has narrowband green emission and excellent stability against air, water, and light. The emission intensity of a CsPbBr3@PI film is maintained at 93% and 90% of the initial intensity after exposure to air for 43 days and immersion in water for 14 days, respectively. In addition, the water contact angle is 105°, indicating that the film has good hydrophobicity. Surprisingly, the film is not broken after repeated bending (1 250 times), and its emission intensity is almost unchanged, which illustrates that the film has excellent flexibility. The good performance of the obtained CsPbBr3@PI films indicates their potential as a backlight source for flexible liquid crystal display applications.

An activator’s selective occupation of a host is of great significance for designing high-quality white light-emitting diode phosphors, while achieving a full-spectrum single-phase white light emission phosphor is challenging. In this study, a boron phosphate solid-solution Na2Y2(BO3)2–x (PO4) x O:0.005 Bi3+ (NYB2–x P x O:0.005 Bi3+) white phosphor was designed by selectively occupying Bi3+ activators in the mixed anionic groups. The substitutes of the anionic unit (BO3)3– by the (PO4)3– unit are supposed to force part of the Bi3+ ion to enter the Na lattice site, which produces an intense orange-red emission peaked at 590 nm. In parallel, spectral tuning from blue to white light and an internal quantum efficiency of 56.42% was obtained, and the thermal stabile luminescence intensity remains at 94.2% of the initial intensity after four heating–cooling cycles from 30 to 210 °C (luminescent intensity is 83.6% of room temperature (RT) at 150 °C, with excellent thermal stability and recovery performance). Finally, an excellent color rendering index (Ra = 90.8 and R9 = 85) was demonstrated for white light-emitting diode devices using only an NYB1.5P0.5O:0.005 Bi3+ phosphor and a near-ultraviolet (n-UV) 365 nm LED chip. This work delves into the different selective occupancy of Bi3+ ions and explores a new avenue for the design of phosphors for full-spectrum white light emission.

Mechanoluminescence (ML) materials have found potential applications in information storage, anti‐counterfeiting, and stress sensing. Conventional stress sensing based on absolute ML intensity is prone to significant mistakes owing to the unpredictability of measurement surroundings. However, implementing a ratiometric ML sensing technique may considerably ameliorate this issue. In this study, a single activator‐doped gallate material (LiGa5O8:Pr3+) is proposed to determine the relationship between the ML intensity and the change in local positional symmetry that occurs when the material is subjected to stress. The sensing reliability of the ML intensity ratio under different factors (Force; Content; Thickness and Materials) is systematically analyzed, where the factor that has the greatest effect on the proportional ML is the concentration, with the ML intensity asymmetry ratio decreasing from 1.868 to 1.300 varying concentration at constant stress. The colour‐resolved visualization of stress sensing is further realized, which opens a new path for a ratiometric ML‐based strategy to improve the reliability of stress sensing.

Luminous properties play an essential role in the phosphor-converted white light-emitting diodes for high-quality illumination, where the self-reducing behavior of doped activators and excellent thermal stability have received significant attention....

Mechanoluminescence (ML) materials, which can emit light under external mechanical stimuli, have attracted wide attention in diverse applications such as display, anti-counterfeiting and 3D signature. However, weak ML intensity and...