Metal halide perovskite quantum dots (QDs) and polymer composite films have witnessed extensive investigation in flexible optoelectronic devices, while the unsatisfactory environmental and mechanical properties of the composite films set substantial limitations for practical applications. Herein, highly luminescent perovskite QDs-polymer composite films (QPFs) are fabricated with remarkable environmental and mechanical stabilities by incorporation of perovskite QDs into fluoroelastomer polymeric matrix. The stretchable QPFs show excellent self-healing ability with micron-and centimeter-scale cracks healed in dozens of minutes and hours, respectively, due to the strong dipole-dipole interaction between the CF bonds of fluoroelastomer. After careful optimization of QDs ratios, a flat and smooth film morphology is achieved with a uniform distribution of QDs, which promotes good optical properties with a long PL lifetime of 1213.75 ns and high photoluminescence quantum yields up to 96.1%, and super environmental and mechanical stability These merits of QPFs enable their practical applications in flexible white light-emitting devices and wide color gamut displays with 124% of standard National Television Standards Committee and 96% of Recommendation 2020, respectively, exhibiting vivid pictures with high saturations for the object colors, indicating great potential toward practical applications.

CsPbX 3 perovskite QDs can be adjusted by controlling size, morphology and com position. In addition, they have exhibited high PLQY, narrow FWHM, strong defect resistance, long carrier lifetime, and PL tunability in the entire visible spectrum range, all of which render this category of materials broad prospects in the field of optoelectronic applications. [7][8][9][10] However, owing to its ionic nature, perovskite QDs are highly susceptible to phase transition and even decomposi tion under various stimulus, including radiation, heat, moisture, oxygen. [11] Such instability problem greatly hinders the practical applications of lead halide perovskite. Besides, high defect density is often reported for colloidal perovskite QDs. These structural and surface defects would destroy the crystalline lattice of CsPbX 3 QDs, making them more vul nerable to external stimuli, and resulting in the rapid degradation of their photo electric performance. [12,13] Moreover, because of their large surface area and rich surface defective sites, inorganic perovskite QDs prepared by colloidal approach often show poor storage stability with high susceptiblity to agglomeration, thus restricting their potential commercial application. [14,15] All-inorganic perovskite quantum dots (QDs) have emerged as a new category of low-cost semiconducting luminescent materials for optoelectronic applications. However, their poor stability has become the main challenge that impedes their potential applications. Herein, Ni-doped CsPbBr 3 QDs with lead phosphate (Pb 3 (PO 4 ) 2 ) shell through surface sacrificial coating (c-Ni-CsPbBr 3 ) have been developed based on a modified thermal injection approach. The synergistic effect of Ni doping and Pb 3 (PO 4 ) 2 coating effectively improves the stability and optical performances of CsPbBr 3 QDs, including photoluminescence (PL) intensity, the average lifetime, and PL quantum yield (QY). Thus, the c-Ni-CsPbBr 3 QDs demonstrate the full width at half maxima (FWHM) and PLQY being 18.42 nm and 90.77%, respectively. The PL intensity of c-Ni-CsPbBr 3 can be maintained at 81% of its original value after being heated at 100 °C for 1 h. No phase transformation can be observed after being stored under ambient conditions (25 °C, 60% relative humidity (RH)) for 21 days. In addition, by combining green c-Ni-CsPbBr 3 QDs, red CdSe-based QDs and the blue GaN chip, a QD enhancement film (QDEF) is fabricated to form a liquid crystal display (LCD) backlit with a wide color gamut covering cover 121% of the National Television System Committee (NTSC) standard.

perovskite has exhibited great potential to be an ideal luminescent material for perovskite light-emitting diodes (PeLEDs). However, the loworder phases (especially n = 1 phase) and the inevitable defects result in massive nonradiative recombination and poor emission efficiency. Herein, a multifunctional molecule of tetrabutylammonium dihydrogen phosphate (TDP) is introduced to simultaneously suppress the low-n phase, passivate the defects, and increase the exciton binding energy of the quasi-2D perovskite for massive radiative recombination and thus high emission efficiency. The multifunctional roles of TDP are realized by the synergistic effects of tetrabutylammonium cation and dihydrogen phosphate anion, both of which show strong interaction with the lead bromide octahedron of the perovskite. As a result, the TDP-incorporated perovskite films show a great enhancement of the emission efficiency with a remarkable increase in photoluminescence quantum yield (PLQY) from 34.6 to 96.9% at the wavelength of 522 nm. The strengthened radiative recombination promotes efficient emission efficiency with over 2.5-fold improvement in external quantum efficiency (EQE) and current efficiency (CE) from 3.27% and 10.83 cd A −1 to 9.25% and 28.35 cd A −1 , respectively, as well as high brightness with over 37% enhancement from 12713 to 17536 cd m −2 . Consequently, this work contributes to an efficient approach to employ a multifunctional molecule for highly emissive quasi-2D perovskites and enhanced quasi-2D PeLED performances.

Multi‐shelled ZnSeTe/ZnSe/ZnS quantum dots (QDs) have served as a promising eco‐friendly emitter for blue quantum dot light‐emitting diodes (QLEDs). While extensive studies have concentrated on the optimization of the shell species and thickness of the multi‐shelled QDs to raise the QLED electroluminescent performance, very few reports focus on the QD surface states involving ligand and defect modulations which are essential for high‐performance QLEDs. Herein, the strategy of bromide decoration is theoretically and practically demonstrated to simultaneously diminish the QD surface defects by passivating the unsaturated Zn for strengthened carrier radiative recombination and removing the superabundant oleic acid through ligand exchange for efficient carrier transport. As a result, the merits of bromide decoration benefit a large increase in photoluminescence quantum yield (PLQY) from 39.7% to 86.2% at the wavelength of 443 nm, as well as a great enhancement of the device performance with over sevenfold improvement in external quantum efficiency (EQE) from 0.74% to 5.46% and a distinct decrease in turn‐on voltage from 6.7 to 5.9 V. Consequently, this work contributes an effective approach of the multi‐shelled QD surface decoration toward enhanced QLED performance.

CsPbI3 perovskite nanocrystals (NCs) are rising as promising photoactive materials for optoelectronic devices. However, the poor phase stability of CsPbI3 NCs has set substantial limitations in their practical application. Herein,...