Tuning the Electrical Transport Properties of Multilayered Molybdenum Disulfide Nanosheets by Intercalating Phosphorus

We demonstrate the tuning of the electrical transport properties of MoS₂ nanosheets by intercalating phosphorus (P). The P-doped MoS₂ nanosheets were synthesized by a facile hydrothermal method. The structures and electrical properties of P-doped MoS₂ nanosheets were systematically investigated by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectrometry, transmission electron microscopy, Raman spectral analysis, adsorption spectra analysis, and Hall measurements. The results indicate that the stacking of the (002) plane in multilayered MoS₂ nanosheets is inhibited and the interlayer spacing is enlarged with the introduction of P atoms. Both experimental results and theoretical calculations indicate that P atoms are much easier to intercalate into the interlayers of MoS₂, compared with substitution of Mo and S, which significantly affects the vibrational modes of Raman spectra. Furthermore, because of the extra electrons introduced by intercalating P atoms, the conductivity of MoS₂ could be gradually modulated from p-type to n-type by increasing the content of intercalated P. This demonstration of tuning the electrical transport properties of MoS₂ could help in the design of electrical and optoelectronic devices based on layered metal dichalcogenides

Coupling P Nanostructures with P‑Doped g‑C₃N₄ As Efficient Visible Light Photocatalysts for H₂ Evolution and RhB Degradation

Fabricating heterostructures to promote the charge separation and doping heteroatom to modulate the band gap of the photocatalysts have been regarded as effective strategies to improve the photocatalytic performance. However, it is still an unresolved issue of doping element and fabricating heterostructures with good contact at the same time. In this study, P nanostructures/P doped graphitic carbon nitride composites (P@P-<i>g</i>-C₃N₄) were successfully composited by a solid reaction route. Various structural characterizations, including X-ray adsorption near edge structure, indicate that P has been doped into g-C₃N₄ and P nanostructures were directly grown on g-C₃N₄ to form heterostructures. As expected, the intimate contacted heterostructured composites exhibit much enhanced light absorption and high-efficiency transfer and separation of photogenerated electron–hole pairs, and consequently, the composites also possess the superior photocatalytic performance in the rapidly degrading RhB and an efficient H₂ production rate of 941.80 μmolh^–1g^–1. Systematical studies combining experimental measurements with theoretical calculations were carried out to expound the underlying reasons behind the distinct performance. This study pave a one-step way to synthesize earth abundant element C, N, and P as novel photocatalysts for photochemical applications

Low Threshold and Ultrastability of One-Step Air-Processed All-Inorganic CsPbX₃ Thin Films toward Full-Color Visible Amplified Spontaneous Emission

All-inorganic perovskites (CsPbX3) with the merits of high stability and remarkable optical gain property are attractive for achieving on-chip coherent light sources. Unfortunately, traditional solution-processed CsPbX3 films suffer from inevitable poor surface integrity and pinhole defects, severely hindering their optical properties. Here, from the perspective of precursor solution chemistry, we use an ionic liquid solvent methylammonium acetate (MAAc) to fabricate compact, pinhole-free, and smooth CsPbX3 thin films in a one-step air process without antisolvent treatment. Optically pumped amplified spontaneous emission (ASE) with a straightforward visible spectral tunability (418–725 nm) is achieved under both nanosecond and femtosecond laser excitation. For the representative CsPbBr3 films, the threshold reaches down to 11.4 μJ cm–2 under nanosecond laser pumping, which is comparable to the value under one-photon femtosecond pumping. The long gain lifetime up to 258.2 ps is revealed by transient absorption spectroscopy. Most importantly, the films show excellent optical stability and humidity stability with no obvious degradation under the pulsed laser irradiation for more than 210 min, stable ASE output under 95% high humidity, and conspicuous ASE after 1000 h of storage in air condition without encapsulation. These results demonstrate that the method of fabricating inorganic perovskite films with an ionic liquid solvent is promising in developing high-performance full-color visible lasers