Synthesis, optical properties and growth process of In2S3 nanoparticles

Simultaneous Conduction and Valence Band Regulation of Indium-Based Quantum Dots for Efficient H2 Photogeneration

Indium-based chalcogenide semiconductors have been served as the promising candidates for solar H₂ evolution reaction, however, the related studies are still in its infancy and the enhancement of efficiency remains a grand challenge. Here, we report that the photocatalytic H₂ evolution activity of quantized indium chalcogenide semiconductors could be dramatically aroused by the co-decoration of transition metal Zn and Cu. Different from the traditional metal ion doping strategies which only focus on narrowing bandgap for robust visible light harvesting, the conduction and valence band are coordinately regulated to realize the bandgap narrowing and the raising of thermodynamic driving force for proton reduction, simultaneously. Therefore, the as-prepared noble metal-free Cu_0.4-ZnIn₂S₄ quantum dots (QDs) exhibits extraordinary activity for photocatalytic H₂ evolution. Under optimal conditions, the Cu_0.4-ZnIn₂S₄ QDs could produce H₂ with the rate of 144.4 μmol h⁻¹ mg⁻¹, 480-fold and 6-fold higher than that of pristine In₂S₃ QDs and Cu-doped In₂S₃ QDs counterparts respectively, which is even comparable with the state-of-the-art cadmium chalcogenides QDs.

A novel application of In2S3 for visible-light-driven photocatalytic inactivation of bacteria: Kinetics, stability, toxicity and mechanism

Photocatalytic bacterial inactivation under visible light emerges as a new alternative to control microbial contamination by utilizing free and renewable sunlight. However, the exploration of highly effective and safe visible-light-driven (VLD) photocatalysts remains an important step toward accessing this new technology. Herein, an eco-friendly photocatalyst, namely Indium Sulfide (In₂S₃), was fabricated through a facile hydrothermal method for VLD photocatalytic inactivation of bacteria. The energy band gap of the as-prepared In₂S₃ was measured as 2.25 eV. As expected, the obtained In₂S₃ photocatalyst showed remarkable inactivation efficiency toward E. coli under fluorescent tubes irradiation. The photocatalytic inactivation kinetic was perfectly fitted by a mathematical model for bacteria inactivation. In addition, In₂S₃ exhibited high stability and could be reused. The leakage of In³⁺ was not significant and showed no toxic effect to the bacteria. Based on the results of scavenger study and ESR technology, the dominant reactive species causing In₂S₃ VLD photocatalytic bacterial inactivation were proposed as O₂^-, h⁺, H₂O₂ and e^-, rather than OH. The SEM study suggested that the damages to the intracellular components occurred prior to the destruction of cell wall. This study provides novel application of In₂S₃ for VLD photocatalytic inactivation of bacteria as well as comprehensive insight into the inactivation mechanism.

TiO2 Nanowire-Supported Sulfide Hybrid Photocatalysts for Durable Solar Hydrogen Production

As the feet of clay, photocorrosion induced by hole accumulation has placed serious limitations on the widespread deployment of sulfide nanostructures for photoelectrochemical (PEC) water splitting. Developing sufficiently stable electrodes to construct durable PEC systems is therefore the key to the realization of solar hydrogen production. Here, an innovative charge-transfer manipulation concept based on the aligned hole transport across the interface has been realized to enhance the photostability of In₂S₃ electrodes toward PEC solar hydrogen production. The concept was realized by conducting compact deposition of In₂S₃ nanocrystals on the TiO₂ nanowire array. Under PEC operation, the supporting TiO₂ nanowires functioned as an anisotropic charge-transfer backbone to arouse aligned charge transport across the TiO₂-In₂S₃ interface. Because of the aligned hole transport, the TiO₂ nanowire-supported In₂S₃ hybrid nanostructures (TiO₂-In₂S₃) exhibited improved hole-transfer dynamics at the TiO₂-In₂S₃ interface and enhanced hole injection kinetics at the electrode surface, substantially increasing the long-term photostability toward solar hydrogen production. The PEC durability tests showed that TiO₂-In₂S₃ electrodes can achieve nearly 90.9% retention of initial photocurrent upon continuous irradiation for 6 h, whereas the pure In₂S₃ merely retained 20.8% of initial photocurrent. This double-gain charge-transfer manipulation concept is expected to convey a viable approach to the intelligent design of highly efficient and sufficiently stable sulfide photocatalysts for sustainable solar fuel generation.

Tunable photoluminescence and room temperature ferromagnetism of In2S3:Dy3+,Tb3+ nanoparticles

In₂S₃:6%Dy³⁺,yTb³⁺ nanoparticles exhibit tunable optical properties and room temperature ferromagnetism, which have been further investigated using VASP calculations.

Excitation dependent multicolor emission and photoconductivity of Mn, Cu doped In2S3 monodisperse quantum dots

Indium sulphide (In2S3) quantum dots (QDs) of average size 6 ± 2 nm and hexagonal nanoplatelets of average size 37 ± 4 nm have been synthesized from indium myristate and indium diethyl dithiocarbamate precursors respectively. The absorbance and emission band was tuned with variation of nanocrytal size from very small in the strong confinement regime to very large in the weak confinement regime. The blue emission and its shifting with size has been explained with the donor-acceptor recombination process. The 3d element doping (Mn(2+) and Cu(2+)) is found to be effective for formation of new emission bands at higher wavelengths. The characteristic peaks of Mn(2+) and Cu(2+) and the modification of In(3+) peaks in the x-ray photoelectric spectrum (XPS) confirm the incorporation of Mn(2+) and Cu(2+) into the In2S3 matrix. The simulation of the electron paramagnetic resonance signal indicates the coexistence of isotropic and axial symmetry for In and S vacancies. Moreover, the majority of Mn(2+) ions and sulphur vacancies (VS ) reside on the surface of nanocrystals. The quantum confinement effect leads to an enhancement of band gap up to 3.65 eV in QDs. The formation of Mn 3d levels between conduction band edge and shallow donor states is evidenced from a systematic variation of emission spectra with the excitation wavelength. In2S3 QDs have been established as efficient sensitizers to Mn and Cu emission centers. Fast and slow components of photoluminescence (PL) decay dynamics in Mn and Cu doped QDs are interpreted in terms of surface and bulk recombination processes. Fast and stable photodetctors with high photocurrent gain are fabricated with Mn and Cu doped QDs and are found to be faster than pure In2S3. The fastest response time in Cu doped QDs is an indication of the most suitable system for photodetector devices.

Ce doping influence on the magnetic phase transition in In2S3:Ce nanoparticles

The classical thermally driven transition from supermagnetic to blocked supermagnetic and quantum phase transition from magnetic long-range order to quantum superparamagnetic state have been observed in ultrasmall In₂S₃:Ce diluted magnetic semiconductors.