A simple and versatile in situ fabrication of MAPbX nanocrystal-embedded polymer composite films is developed by controlling the crystallization process from precursor solutions. The composite films exhibit enhanced photoluminescence properties, improved stability, and excellent piezoelectric and mechanical properties. Applications of these composite films as color converters in liquid-crystal-display backlights are demonstrated, showing bright potential in display technology.

Lead halide perovskite quantum dots (QDs) are promising candidates for future lighting applications, due to their high quantum yield, narrow full width at half maximum (FWHM), and wide color gamut. However, the toxicity of lead represents a potential obstacle to their utilization. Although tin(II) has been used to replace lead in films and QDs, the high intrinsic defect density and oxidation vulnerability typically leads to unsatisfactory material properties. Bismuth, with much lower toxicity than lead, is promising to constitute lead-free perovskite materials because Bi is isoelectronic to Pb and more stable than Sn . Herein we report, for the first time, the synthesis and optical characterization of MA Bi Br perovskite QDs with photoluminescence quantum yield (PLQY) up to 12 %, which is much higher than Sn-based perovskite nanocrystals. Furthermore, the photoluminescence (PL) peaks of MA Bi X QDs could be easily tuned from 360 to 540 nm through anion exchange.

A facile one-step method was developed to fabricate luminescent CH3NH3PbBr3/NaNO3 nanocomposites. Due to the space localization and protection of the tight inorganic salt matrix, the nanocomposites show a longer PL lifetime and enhanced thermal, light, and solvent stability.

Lead halide perovskite quantum dots (QDs) are promising candidates for future lighting applications,d ue to their high quantum yield, narrow full width at half maximum (FWHM), and wide color gamut. However,the toxicity of lead represents ap otential obstacle to their utilization. Although tin(II) has been used to replace lead in films and QDs,the high intrinsic defect density and oxidation vulnerability typically leads to unsatisfactory material properties.Bismuth, with much lower toxicity than lead, is promising to constitute lead-free perovskite materials because Bi 3+ is isoelectronic to Pb 2+ and more stable than Sn 2+ .Herein we report, for the first time,the synthesis and optical characterization of MA 3 Bi 2 Br 9 perovskite QDs with photoluminescence quantum yield (PLQY) up to 12 %, whichi sm uchh igher than Sn-based perovskite nanocrystals.F urthermore,t he photoluminescence (PL) peaks of MA 3 Bi 2 X 9 QDs could be easily tuned from 360 to 540 nm through anion exchange.

Polarized light is very necessary to achieve functional optical systems for display, imaging, and information storage. Luminescent materials with polarized emission are of great interest to achieve polarized light. Here, strong polarized photoluminescence from stretched perovskite‐nanocrystal‐embedded polymer composite films is reported by combining an in situ fabrication process with controllable mechanical stretching. The material characterizations show that perovskite quantum dots (QDs) in stretched composite films are oriented aligned into wires along the stretching direction. The optical measurements illustrate that the stretched composite films exhibit not only isotropic absorption but also polarized photoluminescence emission. This feature can be explained with their unique structure of “QD‐aligned wires”. The achieved polarization ratio is consistent with the calculated results by considering the dielectric confinement of optical electric field and exciton–exciton interactions. In addition, the optimized stretched composite films show strong photoluminescence emission with a polarization ratio of up to 0.33 and a quantum yield of 80%. The use of these composite films in liquid crystal display backlights has potential to increase the light transmittance of polarizers from 50% (without considering the optical loss) to 65%, which is of great significance to improve the energy efficiency.