2D perovskites have emerged as one of the most promising photovoltaic materials owing to their excellent stability compared with their 3D counterparts. However, in typical 2D perovskites, the highly conductive inorganic layers are isolated by large organic cations leading to quantum confinement and thus inferior electrical conductivity across layers. To address this issue, the large organic cations are replaced with small propane-1,3-diammonium (PDA) cations to reduce distance between the inorganic perovskite layers. As shown by optical characterizations, quantum confinement is no longer dominating in the PDA-based 2D perovskites. This leads to considerable enhancement of charge transport as confirmed with electrochemical impedance spectroscopy, time-resolved photoluminescence, and mobility measurements. The improved electric properties of the interlayer-engineered 2D perovskites yield a power conversion efficiency of 13.0%. Furthermore, environmental stabilities of the PDA-based 2D perovskites are improved. PDA-based 2D perovskite solar cells (PSCs) with encapsulation can retain over 90% of their efficiency upon storage for over 1000 h, and PSCs without encapsulation can maintain their initial efficiency at 70 °C for over 100 h, which exhibit promising stabilities. These results reveal excellent optoelectronic properties and intrinsic stabilities of the layered perovskites with reduced interlayer distance.

Nitrogen and sulfur codoped carbon dots (CDs) were prepared from garlic by a hydrothermal method. The as-prepared CDs possess good water dispersibility, strong blue fluorescence emission with a fluorescent quantum yield of 17.5%, and excellent photo and pH stabilities. It is also demonstrated that the fluorescence of CDs are resistant to the interference of metal ions, biomolecules, and high ionic strength environments. Combining with low cytotoxicity properties, CDs could be used as an excellent fluorescent probe for cellular multicolor imaging. Moreover, the CDs were also demonstrated to exhibit favorable radical scavenging activity.

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1T-MoSe2 nanosheets featuring expanded (002) interlayer spacings as large as 1.17 nm are prepared and demonstrated as an efficient electrocatalyst for the hydrogen evolution reaction.

Plate-like copper-substituted P2-type Na0.67CuxMn1−xO2 is able to rapidly charge and discharge within 5 minutes while still giving a capacity of about 90 mA h g−1 at a current of 1000 mA g−1.

We study the formation chemistry of Cl-doped perovskites by examining the chemical interactions between thermally evaporated MAI and PbCl2through X-ray photoemission spectroscopy.

Development of high‐performance and cost‐effective non‐noble metal electrocatalysts is pivotal for the eco‐friendly production of hydrogen through electrolysis and hydrogen energy applications. Herein, the synthesis of an unconventional nickel nitride nanostructure enriched with nitrogen vacancies (Ni3N1− x) through plasma‐enhanced nitridation of commercial Ni foam (NF) is reported. The self‐supported Ni3N1− x/NF electrode can deliver a hydrogen evolution reaction (HER) activity competitive to commercial Pt/C catalyst in alkaline condition (i.e., an overpotential of 55 mV at 10 mA cm−2 and a Tafel slope of 54 mV dec−1), which is much superior to the stoichiometric Ni3N, and is the best among all nitride‐based HER electrocatalysts in alkaline media reported thus far. Based on theoretical calculations, it is further verified that the presence of nitrogen vacancies effectively enhances the adsorption of water molecules and ameliorates the adsorption–desorption behavior of intermediately adsorbed hydrogen, which leads to an advanced HER activity of Ni3N1− x/NF.

It has been generally believed and assumed that organometal halide perovskites would form type II P–N junctions with fullerene derivatives (C60 or PCBM), and the P–N junctions would provide driving force for exciton dissociation in perovskite‐based solar cell. To the best of our knowledge, there is so far no experiment proof on this assumption. On the other hand, whether photogenerated excitons can intrinsically dissociate into free carrier in the perovskite without any assistance from a P–N junction is still controversial. To address these, the interfacial electronic structures of a vacuum‐deposited perovskite/C60 and a solution‐processed perovskite/PCBM junctions is directly measured by ultraviolet photoelectron spectroscopy. Contrary to the common believes, both junctions are found to be type I N–N junctions with band gap of the perovskites embedded by that of the fullerenes. Meanwhile, device with such a charge inert junction can still effectively functions as a solar cell. These results give direct experimental evidence that excitons are dissociated to free carriers in the perovskite film even without any assistance from a P–N junction.