Titanate nanofibers sensitized with nanocrystalline Bi2S3 as new electrocatalytic materials for ascorbic acid sensor applications

Improvement in Optoelectronic Properties of Bismuth Sulphide Thin Films by Chromium Incorporation at the Orthorhombic Crystal Lattice for Photovoltaic Applications

By using the chemical bath deposition approach, binary bismuth sulphides (Bi₂S₃) and chromium-doped ternary bismuth sulphides (Bi_2−xCr_xS₃) thin films were effectively produced, and their potential for photovoltaic applications was examined. Structural elucidation revealed that Bi₂S₃ deposited by this simple and cost-effective method retained its orthorhombic crystal lattice by doping up to 3 at.%. The morphological analysis confirmed the crack-free deposition, hence making them suitable for solar cell applications. Optical analysis showed that deposited thin films have a bandgap in the range of 1.30 to 1.17 eV, values of refractive index (n) from 2.9 to 1.3, and an extinction coefficient (k) from 1.03 to 0.3. From the Hall measurements, it followed that the dominant carriers in all doped and undoped samples are electrons, and the carrier density in doped samples is almost two orders of magnitude larger than in Bi₂S₃. Hence, this suggests that doping is an effective tool to improve the optoelectronic behavior of Bi₂S₃ thin films by engineering the compositional, structural, and morphological properties.

Bi2S3/rGO Composite Based Electrochemical Sensor for Ascorbic Acid Detection

The engineering of an efficient electrochemical sensor based on a bismuth sulfide/reduced graphene oxide (Bi2S3/rGO) composite to detect ascorbic acid (AA) is reported. The Bi2S3 nanorods/rGO composite was synthesized using a facile hydrothermal method. By varying the amount of graphene oxide (GO) added to the synthesis, the morphology and size of Bi2S3 nanorods anchored on the surface of rGO can be tuned. Compared to a bare glassy carbon electrode (GCE), the GCE modified with Bi2S3/rGO composite presented enhanced electrochemical performance, which was attributed to the optimal electron transport between the rGO support and the loaded Bi2S3 as well as to an increase in the number of active catalytic sites. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analysis of Bi2S3/rGO/GCE demonstrate that the active Bi2S3/rGO layer on GCE plays an important role in the electrochemical behavior of the sensor. In particular, the Bi2S3/rGO/GCE sensor shows a wide detecting range (5.0–1200 μM), low detection limit (2.9 µM), good sensitivity (268.8 μA mM−1 cm−2), and sufficient recovery values (97.1–101.6%) for the detection of ascorbic acid.

Photoluminescence emission from nanostructured porous preparations of CdS-ZnTiO3 assembled nanoparticles

This study reports the structural and optical properties of CdS/ZnTiO₃ nanocomposites prepared using a chemical bath and different titanate concentrations. Commercial ZnTiO₃ nanoparticles were introduced into a chemical bath that had been used to produce CdS semiconductor nanoparticles (NPs). Here, the growing CdS crystallites precipitated onto the suspended zinc titanate NPs. X-ray diffraction patterns revealed that samples of CdS/ZnTiO₃ nanopowders were made of cubic ZnTiO₃ and hexagonal CdS wurtzite. The morphology of the particles was studied using transmission electron microscopy and scanning electron microscopy images. These images demonstrated the different characteristics of the CdS/ZnTiO₃ nanocomposites and their dependence on titanate concentration when placed into the CdS-growing solution. Photoluminescence spectra showed three main emission bands for the electron transitions in the CdS/ZnTiO₃ composite. This composite produced three photoluminescence bands, the intensities of which depended on composite shape, which in turn depended on the relative concentrations of CdS and ZnTiO₃ .

Design of Double-Shelled CuS Nanocages to Optimize Electrocatalytic Dynamic for Sensitive Detection of Ascorbic Acid

Although transition metal sulfides have presented prospect in electrochemical sensing, their electrocatalytic performance still cannot meet the demands for practical applications due to the difficulties in mass transport and electron transfer. In this work, double-shelled CuS nanocages (2-CuS NCs) were prepared for enzyme-free ascorbic (AA) sensor through a Cu2O- templated method. The unique double-shelled hollow structure displayed large specific surface areas, ordered diffusion channels, increased volume occupying rate, and accelerated electron transfer rate, resulting in enhanced electrochemical dynamic. As a sensing electrode for AA, 2-CuS NCs modified glassy carbon electrode (2-CuS NCs/GCE) exhibited eminent electrocatalytic activity in terms of satisfying sensitivity (523.7 μA mM-1 cm-2), short response time (0.31 s), and low limit of detection (LOD, 0.15 μM). 2-CuS NCs look promising for analytical sensing of AA in electrochemical sensors thanks to its prominent electrocatalytic kinetics issued from double-shelled hollow porous structure.

Facile fabrication and characterization of two-dimensional bismuth(iii) sulfide nanosheets for high-performance photodetector applications under ambient conditions

Two-dimensional (2D) bismuth(iii) sulfide (Bi₂S₃) nanosheets as non-toxic graphene-like nanomaterials were successfully fabricated by a facile liquid phase exfoliation (LPE) method. A robust photodetector employing a Bi₂S₃ nanosheet film has been fabricated for the first time via a facile fabrication process on an ITO-coated glass. UV-Vis and Raman spectroscopy techniques were carried out and they confirmed the inherent optical and physical properties of Bi₂S₃ nanosheets. Photoelectrochemical (PEC) measurements demonstrate that a significantly higher photocurrent density (42 μA cm^-2) and enhanced photoresponsivity (210 μA W^-1), at a lower bias potential in alkaline solution, of the Bi₂S₃ nanosheet-based photodetector are achieved, compared with those of other 2D nanomaterial-based photodetectors under light irradiation. Furthermore, the as-prepared Bi₂S₃ nanosheet-based photodetector not only exhibits an appropriate capacity of self-driven broadband and high-performance photoresponse but also displays strong long-term stability of the ON/OFF switching behaviour without any external protection in alkaline solutions. Because of facile synthesis via a LPE method, a higher photocurrent density and photoresponsivity, self-driven performance and long-term stability of the Bi₂S₃ nanosheet-based photodetector at a lower bias potential in alkaline solutions, the present work can provide fundamental acknowledgement of the high performance of this new kind of PEC-type 2D nanosheet-based photodetector.

Chemiluminescence determination of ascorbic acid using graphene oxide@copper-based metal–organic frameworks as a catalyst

In this work, composites with different amounts of graphene oxide (GO) and the copper-based metal–organic frameworks (HKUST-1) were synthesized.

Novel one-pot synthesis and sensitisation of new BiOCl–Bi2S3 nanostructures from DES medium displaying high photocatalytic activity

A novel one-pot synthetic procedure yields hierarchically nanostructured BiOCl–Bi₂S₃ nanoparticles with improved photocatalytic activity towards degradation of rhodamine B.

Amperometric sensor for ascorbic acid using a gold electrode modified with ZnO@SiO2 nanospheres

A highly sensitive sensor based on ZnO@SiO₂ nanospheres has been developed for the detection of ascorbic acid. The developed sensor is very simple and has been fabricated using low cost materials.