Inorganic perovskites with special semiconducting properties and structures have attracted great attention and are regarded as next generation candidates for optoelectronic devices. Herein, using a physical vapor deposition process with a controlled excess of PbBr , dual-phase all-inorganic perovskite composite CsPbBr -CsPb Br thin films are prepared as light-harvesting layers and incorporated in a photodetector (PD). The PD has a high responsivity and detectivity of 0.375 A W and 10 Jones, respectively, and a fast response time (from 10% to 90% of the maximum photocurrent) of ≈280 µs/640 µs. The device also shows an excellent stability in air for more than 65 d without encapsulation. Tetragonal CsPb Br provides satisfactory passivation to reduce the recombination of the charge carriers, and with its lower free energy, it enhances the stability of the inorganic perovskite devices. Remarkably, the same inorganic perovskite photodetector is also highly flexible and exhibits an exceptional bending performance (>1000 cycles). These results highlight the great potential of dual-phase inorganic perovskite films in the development of optoelectronic devices, especially for flexible device applications.

MXenes have been demonstrated as a potential candidate in the field of photovoltaics and energy storage owing to their high transmittance, metallic conductivity and tunable work function.

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Halogen vacancies are of great concern in blue‐emitting perovskite quantum‐dot light‐emitting diodes because they affect their efficiency and spectral shift. Here, an enriched‐bromine surface state is realized using a facile strategy that employs a PbBr2 stock solution for anion exchange based on Cd‐doped perovskite quantum dots. It is found that the doped Cd ions are expected to reduce the formation energy of halogen vacancies filled by the external bromine ions, and the excess free bromine ions in solution are enriched in the surface by anchoring with halogen vacancies as sites, accompanied with the shedding of surface long‐chain ligands during the anion exchange process, resulting in a Br‐rich and “neat” surface. Moreover, the surface state exhibits good passivation of the surface defects of the controlled perovskite QDs and simultaneously increases the exciton binding energy, leading to excellent optical properties and stability. Finally, the sky‐blue emitting perovskite quantum‐dot light‐emitting diodes (QLEDs) (490 nm) are conducted with a record external quantum efficiency of 14.6% and current efficiency of 19.9 cd A−1. Meanwhile, the electroluminescence spectra exhibit great stability with negligible shifts under a constant operating voltage from 3 to 7 V. This strategy paves the way for improving the efficiency and stability of perovskite QLEDs.

We report a simple, robust, and inexpensive strategy to enable all-inorganic CsPbX3 perovskite nanocrystals (NCs) with a set of markedly improved stabilities, that is, water stability, compositional stability, phase stability, and phase segregation stability via impregnating them in solid organic salt matrices (i.e., metal stearate; MSt). In addition to acting as matrices, MSt also functions as the ligand bound to the surface of CsPbX3 NCs, thereby eliminating the potential damage of NCs commonly encountered during purification as in copious past work. Quite intriguingly, the resulting CsPbX3–MSt nanocomposites display an outstanding suite of stabilities. First, they retain high emission in the presence of water because of the insolubility of MSt in water, signifying their excellent water stability. Second, anion exchange between CsPbBr3–MSt and CsPbI3–MSt nanocomposites is greatly suppressed. This can be ascribed to the efficient coating of MSt, thus effectively isolating the contact between CsPbBr3 and CsPbI3 NCs, reflecting notable compositional stability. Third, remarkably, after being impregnated by MSt, the resulting CsPbI3–MSt nanocomposites sustain the cubic phase of CsPbI3 and high emission, manifesting the strikingly improved phase stability. Finally, phase segregation of CsPbBr1.5I1.5 NCs is arrested via the MSt encapsulation (i.e., no formation of the respective CsPbBr3 and CsPbI3), thus rendering pure and stable photoluminescence (i.e., demonstration of phase segregation stability). Notably, when assembled into typical white light-emitting diode architecture, CsPbBr1.5I1.5–MSt nanocomposites exhibit appealing performance, including a high color rendering index (R a) and a low color temperature (T c). As such, the judicious encapsulation of perovskite NCs into organic salts represents a facile and robust strategy for creating high-quality solid-state luminophores for use in optoelectronic devices.

Using {100} plane-capped cubic K0.33FeFe(CN)6/RGO as the cathode, an initial discharge–charge capacity of 159–161 mA h g−1 at 0.5C, and a superior capacity retention of 90.1% at 10C after 500 cycles can be obtained.

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Low-cost manganese hexacyanoferrate (NMHCF) possesses many favorable advantages including high theoretical capacity, ease of preparation, and robust open channels that enable faster Na diffusion kinetics. However, high lattice water and low electronic conductivity are the main bottlenecks to their pragmatic realization. Here, we present a strategy by anchoring NMHCF on reduced graphene oxide (RGO) to alleviate these problems, featuring a specific discharge capacity of 161/121 mA h g at a current density of 20/200 mA g. Moreover, the sodiation process is well revealed by ex situ X-ray diffraction, EIS and Car-Parrinello molecular dynamics simulations. At a rate of 20 mA g, the hard carbon//NMHCF/RGO full cell affords a stable discharge capacity of 84 mA h g (based on the weights of cathode mass) over 50 cycles, thus highlighting NMHCF/RGO an alternative cathode for sodium-ion batteries.