Superlattices have attracted great interest because of their tailorable electronic properties at the interface. However, the lack of an efficient and low-cost synthetic method represents a huge challenge to implement superlattices into practical applications. Herein, we report a space-confined nanoreactor strategy to synthesize flexible freestanding graphene-based superlattice nanosheets, which consist of alternately intercalated monolayered metal-oxide frameworks and graphene. Taking vanadium oxide as an example, clear-cut evidences in extended X-ray absorption fine structure, high-resolution transmission electron microscopy and infrared spectra have confirmed that the vanadium oxide frameworks in the superlattice nanosheets show high symmetry derived from the space-confinement and electron-donor effect of graphene layers, which enable the superlattice nanosheets to show emerging magnetocaloric effect. Undoubtedly, this freestanding and flexible superlattice synthesized from a low-cost and scalable method avoids complex transferring processes from growth substrates for final applications and thus should be beneficial to a wide variety of functionalized devices.

Optical clearing methods can facilitate deep optical imaging in biological tissue by reducing light scattering and this has enabled accurate three-dimensional signal visualization and quantification of complex biological structures. Unfortunately, existing optical clearing approaches present a compromise between maximizing clearing capability, the preservation of fluorescent protein emission and membrane integrity and the speed of sample processing – with the latter typically requiring weeks for cm scale tissue samples. To address this challenge, we present a new, convenient, aqueous optical clearing agent, termed UbasM: Urea-Based Amino-Sugar Mixture, that rapidly renders fixed tissue samples highly transparent and reliably preserves emission from fluorescent proteins and lipophilic dyes in membrane integrity preserved tissues. UbasM is simple, inexpensive, reproducible and compatible with all labeling methods that we have encountered. It can enable convenient, volumetric imaging of tissue up to the scale of whole adult mouse organs and should be useful for a wide range of light microscopy and tomography techniques applied to biomedical research, especially the study on organism-level systems biology at multiple levels.

Magnetic nanoring structures are attractive for spintronic devices due to their unique attributes of well‐defined and reproducible magnetic states originating from their characteristic geometry. Almost all previous magnetic nanorings have been exclusively limited to traditional ferromagnetic materials, and a magnetic semiconductor (MSC) nanoring structure has been reported rarely during the past decades. Here, it is demonstrated that room‐temperature ferromagnetic Ag1.2V3O8 nanobelts and nanorings may be achieved by controlled oxidation of the V4+ precursors in an Ag+‐containing aqueous solution. The polarization‐induced self‐coiling of in situ formed Ag1.2V3O8 nanobelts is responsible for the formation of the perfectly circular nanoring geometry. The NEXAFS spectra and the density functional calculations clearly reveal that the electron transfer originates from the hybridization of the doped Ag+ and V4+ atoms, causing ordering of the magnetic moments that give rise to the intrinsic ferromagnetism of the Ag1.2V3O8 structure.

Perovskite quantum dots (QDs) have gained significant attention for both fundamental research and commercial applications because of their outstanding optoelectronic properties and tremendous application potentials. Reducing defect density in all-inorganic perovskite QDs is of great importance for performance enhancement. In this work, it is found that the UV-NIR femtosecond laser pulse treatments could increase the photoluminescence quantum yield (PLQY) of the CsPbBr 3 perovskite QDs from 71 to 95%. Such an enhancement could be attributed to decrease of the defects after laser exposure, which is consistent with its red-shifted PL and other characterization results. Furthermore, the dynamics of energy transfer from exciton to trapping in irradiated CsPbX 3 QDs are studied to gain an insight into the relative strength of exciton-trapping exchange coupling. The results confirm that the trapping defects are decreased by laser irradiation, and the mechanism leading to the enhancement of PLQY is revealed. In addition, the enhanced stability of laser-irradiated CsPbX 3 QDs is also testified. Finally, the application of laser-treated perovskite QDs in the liquid crystal display (LCD) backlight film is successfully demonstrated. It is further anticipated that this mechanism is helpful for the design of perovskite-based optoelectronic applications such as LCD technology and light-emitting devices.

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Schematic diagram of the perovskite photodetector under proton irradiation and the degradation mechanism of the functional layer after irradiation.

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