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Phase‐junction nanocomposites, made of nanograins with the same composition but different phases, offer a platform to optimize the physiochemical performance of materials. Herein, we demonstrate a straightforward strategy to synthesize Cu2−xS phase‐junction nanocomposites by retaining surface 1‐dodecanethiol (DDT) ligands, in contrast to the traditional method that strips the ligands. As a result, phase junctions between a conventional monoclinic (m) phase and an unconventional metastable tetragonal (t) phase are obtained. The significantly improved power factor is obtained due to the doping of the t‐phase. The phase‐junction interfaces reduce thermal conductivity. Finally, surface regulation of phase junctions pushes the peak zT to 2.1 at 932 K, being the highest reported for environment‐friendly metal sulfides. This work provides a paradigm to optimize thermoelectric performance by controlling phase junctions through surface‐ligand tuning. [ABSTRACT FROM AUTHOR]

Improving proton conductivity and fabricating viable metal‐organic frameworks (MOFs) based proton exchange membranes (PEMs) are central issues exploiting electrolyte MOFs. We aim to design multivariate flexibility synergistic strategy to achieve Flexible MOFs (FMOFs) with high conductivity at a wide range of humidity. In situ powder X‐ray diffraction (PXRD) and temperature‐dependent Fourier transform infrared spectra (FT‐IR) prove the synergistic self‐adaption between dynamic torsion of alkyl sulfonic acid and dynamic breathing of FMOF, forming a continuous hydrogen‐bonding networks to maintain high conductivity. Based on the convincing proton conductivity, we construct a series of long‐term durable MOF‐based PEMs that serve as a bridge between MOF and fuel cell. Consequently, the membrane electrode assembly (MEA) of the flexible PMNS1‐40 exhibits a maximum single‐cell power density of 34.76 mW cm−2 and hopefully opens doors to evaluate the practical application of proton‐conducting MOFs in direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

Herein we report two new TPE‐based 3D MOFs, that is, Sr‐ETTB and Co‐ETTB (TPE=Tetraphenylethylene, H8ETTB=4′,4′′′,4′′′′′,4′′′′′′′‐(ethene‐1,1,2,2‐tetrayl)tetrakis(([1,1′‐biphenyl]‐3,5‐dicarboxylic acid))). Through tailoring outer shell electron configurations of SrII and CoII cations, the fluorescence intensity of the MOFs is tuned from high emission to complete non‐emission. Sr‐ETTB with strong blue fluorescence shows reversible fluorescence variations in response to pressure and temperature, which is directly related to the reversible deformation of the crystal structure. In addition, non‐emissive Co‐ETTB counterpart exhibits a turn‐on fluorescent enhancement under the stimulation of analyte histidine. In the process, TPE‐cored linkers in the MOFs are released through competitive coordination substitution and subsequently reassembled to perform aggregation‐induced luminescence behavior originated from the organic linkers. [ABSTRACT FROM AUTHOR]

Herein, we report the facile growth of three‐dimensional CsPbBr3 perovskite supercrystals (PSCs) self‐assembled from individual CsPbBr3 perovskite quantum dots (PQDs). By varying the carbon chain length of a surface‐bound ligand molecule, 1‐alkynyl acid, different morphologies of PSCs were obtained accompanied by an over 1000‐fold photoluminescence improvement compared with that of PQDs. Systematic analyses have shown, for the first time, that under UV irradiation, CsBr, the byproduct formed during PQDs synthesis, could effectively catalyze the homocoupling reaction between two alkynyl groups, which further worked as a driving force to push forward the self‐assembly of PQDs. [ABSTRACT FROM AUTHOR]