Yang Li

Hybrid organic–inorganic metal halide perovskite nanocrystals (NCs) are among the candidates for color conversion materials in displays, especially in NC-based micro-light-emitting diode (micro-LED) displays. However, these NCs are still lacking long-term stability, which has hindered their large-scale applications. We mimic the working conditions, which include ultraviolet light illumination at 323 K and three different types of atmosphere (N₂, vacuum, and air), respectively, to investigate the stability of CH₃NH₃PbBr₃ NCs embedded in the polyvinylidene fluoride matrix. X-ray diffraction results indicate the generation of NH₄Pb₂Br₅, which is produced from the encapsulated CH₃NH₃PbBr₃ NCs in all three atmospheres, and the decomposition generates a large amount of accompanying interface defects at the surface area of NCs, resulting in the significant decrease of the photoluminescence (PL) intensity. This work highlights the stability-related mechanism of CH₃NH₃PbBr₃ NCs under combined external stresses that mimic operating conditions. In addition, this work also suggests a new method for conducting aging tests and contributes to developing effective routes towards higher stability of perovskite NCs.

Poor stability always restricts the application of all-inorganic perovskite quantum dots (PQDs). Herein, 2D hexagonal boron nitride (h-BN) nanosheets were firstly utilized to stabilize CsPbBr₃ PQDs through a facile heterogeneous nucleation-growth process at room temperature. In the synthesized h-BN/CsPbBr₃ PQD nanocomposites, cubic CsPbBr₃ PQDs adhere on h-BN nanosheet surfaces benefiting from the high specific surface area and abundant mesopores of the 2D nanosheets. The nanocomposites prepared at optimized loading of h-BN nanosheets and reaction time display good green-emitting performance with a narrow full width at half maximum of ~20.0 nm and high color purity of 92.0%. Unique 2D structure and excellent thermal conductivity of h-BN nanosheets endow the h-BN/CsPbBr₃ PQD nanocomposites with significantly enhanced humidity-stability and thermal-stability. The white light-emitting diodes (LEDs) assembled with the green-emitting nanocomposites, a blue chip and a commercial red phosphor possess a low correlated color temperature of 4190 K, a color-rendering index of 76 and a high luminous efficacy of 57 lm/W. Further, the color gamut of the synthetic white light based on blue-emitting h-BN/CsPbBr_1.5Cl_1.5 PQDs, green-emitting h-BN/CsPbBr₃ PQDs and red-emitting h-BN/CsPbBr_1.2I_1.8 PQDs is 114% of the National Television System Committee standard. This work paves a new way for utilizing 2D nanomaterials to synthesize stable all-inorganic PQDs for white LEDs and displays.

Breathable and wearable energy storage is achieved based on an innovative design solution. Carbon nanotube/MnO₂-decorated air-laid paper electrodes, with outstanding flexibility and good electrochemical performances, are prepared. They are then assembled into solid-state supercapacitors. By making through-holes on the supercapacitors, breathable and flexible supercapacitors are successfully fabricated.

Currently-developed flexible electrodes/supercapacitors are summarized according a hierarchical and detailed classification strategy.

High‐performance flexible textile electrodes and fiber electrodes are produced simultaneously by a newly proposed effective strategy. Activated carbon fiber cloth (ACFC)/carbon nanotubes (CNTs) and ACFC/MnO₂/CNTs composites are designed as high‐performance flexible textile electrodes. Theses textiles can also be easily dismantled into individual fiber bundles used as high‐performance flexible fiber electrodes.