Machine learning is used to study growth of a metal-organic framework (MOF) in a high-dimensional synthetic space. Neural networks for image processing also provide tools for automatically measuring thickness and lateral size of MOF nanoplates to provide quantitative data for further analysis. Relationships among different quantities in these synthetic endeavors were searched and evaluated with state-of-the-art mathematical tools. This works highlights new opportunities in using machine learning to expedite materials development and provides insight into their synthesis process.

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Broadband near infrared (NIR) emission materials are of interest for various applications including non-destructive biomedical imaging. In this work, ytterbium ion (Yb3+) were successfully doped into Cs2AgInCl6: Cr3+ (i.e. CAIC:...

Excited state energies on a two-dimensional light-harvesting metal–organic layer (MOL) are efficiently transported to Re- and Ir-based reaction centers for converting CO2 to CO or HCOOH.

Metal-organic layers (MOLs) are highly attractive for application in catalysis, separation, sensing and biomedicine, owing to their tunable framework structure. However, it is challenging to obtain comprehensive information about the formation and local structures of MOLs using standard electron microscopy methods due to serious damage under electron beam irradiation. Here, we investigate the growth processes and local structures of MOLs utilizing a combination of liquid-phase transmission electron microscopy, cryogenic electron microscopy and electron ptychography. Our results show a multistep formation process, where precursor clusters first form in solution, then they are complexed with ligands to form non-crystalline solids, followed by the arrangement of the cluster-ligand complex into crystalline sheets, with additional possible growth by the addition of clusters to surface edges. Moreover, high-resolution imaging allows us to identify missing clusters, dislocations, loop and flat surface terminations and ligand connectors in the MOLs. Our observations provide insights into controllable MOL crystal morphology, defect engineering, and surface modification, thus assisting novel MOL design and synthesis.

With nontoxicity and high emission efficiency, luminescent copper­(I)-based halides have attracted much attention as alternatives for lead-based perovskites in photoelectric domains. However, extending the emission wavelength by doping with Mn2+ in a facile way is still a challenge. In this work, Mn2+-doped Cs3Cu2I5 microcrystals were synthesized by a mild solution method, and double emission bands from self-trapped excitons (STEs) and Mn2+ peaking at 445 and 560 nm, respectively, were observed. More importantly, further introduction of alkali metal ions (Rb+, K+, Na+) considerably promoted the luminescence performance of the Cs3Cu2I5–Mn microcrystals. The STE → Mn2+ energy transfer efficiency of the typical sample doped with Na+ increased from ∼0 to 21.30%, and the photoluminescence quantum yield (PLQY) increased from 47.32% to 62.06%. The detailed structural and optical characterizations combined with DFT calculations proved that the doping with alkali metal ions causes lattice distortion and enhances the coupling between [MnI4] and [CuI4] tetrahedra, thus promoting the energy transfer efficiency and the PLQY.

Broadband near-infrared (NIR) materials have recently evoked considerable interest for versatile applications, but the choices of efficient emitters for NIR phosphors are rather limited. Herein, Fe3+-activated NaScSi2O6 phosphor has been...

Metal–organic frameworks (MOFs) based on 9,10-diphenylanthracene-derived ligands had been reported to exhibit upconverted fluorescence through triplet–triplet annihilation. We found that zirconium MOFs based on 9,10-diphenylanthracene can also give upconverted fluorescence via two-photon absorption without adding a triplet photosensitizer when a femtosecond pulsed laser is used as the excitation source. By tuning the synthetic condition, we obtained nanoscale MOFs of UiO structure in both octahedral and hexagonal nanoplate shapes, as well as a hexagonal nanoplate of MOFs of hcp-UiO structure and two-dimensional metal–organic layers. All of them, as well as a homogeneous solution of the 9,10-diphenylanthracene ligand, exhibit upconverted fluorescence upon excitation using a laser pulse of 60 fs with a pulse energy of ∼1.1 × 106 nJ/cm2 (unfocused). Moreover, we observed different emission spectra by two-photon excitation compared to those by one-photon excitation, which indicates access to a unique initial excited state via two-photon excitation. This phenomenon is not observed for a homogeneous solution of the ligand. These nanoscale MOFs may find application in two-photon fluorescence imaging.