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[Display omitted] • CsPbBr 3 with quantum-limited domain effects have reversible hydrochromic properties. • Different Organic solvents cause polarity-related discoloration of composites. • A detection model was developed for all-organic solvent polarity detection. Hydrochromic materials have received much attention in anticounterfeiting due to their reversible photoemission properties toward water. However, existing hydrochromic materials usually suffer from slow hydrochromic response and limited stability, repeatability, and color tunability. This paper found for the first time that CsPbBr 3 /Cs 4 PbBr 6 composites with quantum-limited domain effects had reversible hydrochromism. CsPbBr 3 /Cs 4 PbBr 6 composites were successfully synthesized in molecular sieve MCM-41 using an improved mechanochemical method. The composites underwent a reversible phase transition from Cs 4 PbBr 6 /CsPbBr 3 to CsPbBr 3 upon treatment with a trace amount of water, the photoluminescence colors underwent a change from blue to green, and reversion occurred due to heating. Mechanistic investigation revealed that quantum dots underwent soft agglomeration due to van der Waals forces in polar solvent environments, affecting the action of quantum domain-limiting effects. Therefore, organic solvents with different polarities can cause different degrees of reversible discoloration of the material. This study provides new ideas for understanding the phase transition and agglomeration of metal halide perovskite quantum dots in polar solvent environments. Additionally, it offered new options for aqueous color-changing materials and organic solvent polar detection materials. [ABSTRACT FROM AUTHOR]

• Encapsulating CsPbBr 3 in layered B 2 O 3 via water-induced glass phase transition. • The Luminous performance and stability of CsPbBr 3 NCs are improved. • The prepared LCD covers 130% of the NTSC standard color gamut area. Lead halide perovskite quantum dots are considered to be one of the best candidates for the next generation of light conversion materials. However, their practical application is greatly hindered by its intrinsic poor stability and once exposed to air, heat moisture and illumination. Here, we report a novel reaction scheme that allows the simultaneous production of high-quality CsPbBr 3 nanocrystals (NCs), self-healing process that optimized the crystallinity of CsPbBr 3 NCs, and the formation of a protective coating layered structure of a densely packed two-dimensional B 2 O 3 crystals with the assistance of water. Due to the inherent refractive index mismatch in the B 2 O 3 -CsPbBr 3 -B 2 O 3 (B-C-B) laminated structure, excellent light extraction efficiency was achieved. The resulted layered B 2 O 3 /CsPbBr 3 perovskite composite showed exceptionally high photoluminescence quantum yield (PLQY ∼90%) and excellent stability over 2 years under normal storage condition. A high-performance backlight liquid crystal display (LCD) was designed as B 2 O 3 /CsPbBr 3 @ K 2 SiF 6 : Mn4+ (KSF: Mn4+) @ polydimethylsiloxanes (PDMS) monolithic film, which featured an optimal white emission (with correlated color temperature of 5327 K), that covered 130% of NTSC standard color gamut area of CIE1931, thereby demonstrating a great application potential in the optoelectronics industry. [ABSTRACT FROM AUTHOR]

• The poly(N-isopropyl acrylamide) (PNIPAM)/graphene oxide (GO) mixed system gives temperature-responsive phase separation. • The phase separation produces a gel phase and a water phase. • Metal ions can be adsorbed on GO surface and then transferred into the gel phase. • The phase separation can achieve efficient removal of metal ions from polluted water in an extraction-like process. A temperature-responsive phase separation system based on poly(N-isopropyl acrylamide) (PNIPAM) and graphene oxide (GO) has been developed for efficient removal of metal ions from polluted water. PNIPAM undergoes a coil-to-globule conformational transition upon temperature increase to above its lower critical solution temperature (LCST), which can induce phase separation of the system into a condensed gel phase and a water phase. In this process all GO sheets can be transferred to the gel phase by having strong interactions with PNIPAM molecules via hydrophobic interaction, electrostatic interaction, and hydrogen bonding. Moreover, by having abundant carboxyl, hydroxyl, and epoxy groups to chelate with heavy metal ions, GO sheets can adsorb metal ions efficiently and enrich them into the gel phase. The gel phase can then be separated from the water phase in an extraction-like process, achieving easy removal of the pollutant metal ions from water. This method takes advantages of PNIPAM's temperature responsive phase transition and GO's high adsorption capacity, enabling high versatility, easy treatment and separation, and good reusability in treatment of metal ion pollutions, being highly potential for practical industry applications. [ABSTRACT FROM AUTHOR]