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The development of a low-cost and high-performance electrode for water electrolysis is important for green energy development. In this paper, fluorine-based multi-halogen atom doped carbon quantum dot loaded vertical graphene electrodes are prepared using biomass waste vinasse as a carbon source. F and Cl co-doping has the best electrochemical properties among multi-halogen atom doping. The HER overpotentials of FCl-CQDs/VG at a current density of 10 mA cm−2 are 171 mV and 161 mV at 1 M KOH and 0.5 M H 2 SO 4 , and the OER overpotentials are 393 mV and 556 mV at 1 M KOH and 0.5 M H 2 SO 4 , respectively. The Faraday efficiencies of FCl-CQDs/VG are 89 % (HER) and 86.5 % (OER), respectively. Cl atom doping can increase the content of ionic and semi-ionic bonds C–F, accelerate charge transfer, and improve electrochemical performance. This study improves the basis and ideas for the development of low-cost and high-performance self-supported all-carbon electrodes. [Display omitted] • F-based multi-halogen atom doped vinasse-based all-carbon electrode prepared. • FCl-CQDs/VG has excellent performance and stability for overall water splitting. • Cl doping promotes charge transfer and electronic structure of ionic bond C–F. [ABSTRACT FROM AUTHOR]

PbS/silicon composite photodetection structure can effectively extend the detection wavelength of silicon-based detectors to the near-infrared band, which is an efficient way that enables silicon optical integrated in situ detection. Currently, in most research, PbS colloidal quantum dots (QDs) are prepared by method of metal organic chemistry and ligand exchange, featuring monodispersity, narrow-band absorption and optical response, which makes it difficult to offer broadband response; with a large amount of organic ligand residues on their surface, such QDs are susceptible to the environment and lack stability. In this paper, polydisperse PbS QDs are successfully deposited on the surface of silicon nanowires (Si-NWs) array to form a device with a core-shell structure by successive ionic layer adsorption and reaction method (SILAR). This kind of device allows broad-band absorption and photoelectric response (400–2200 nm), and shows remarkable stability in the atmospheric environment and durability. The test results show that the as prepared polydisperse PbS QDs have a grain size ranging from 3 nm to 15 nm and notably outperform monodisperse colloidal QDs, which can remain stable only when their grain sizes are less than 4 nm. The PbS QDs achieve superb performance in absorption within the wide spectrum range of 400–2500 nm, and the device detectivity can reach 2.18 × 1010 Jones, 2.23 × 109 Jones, 1.75 × 108 Jones and 2.23 × 107 Jones at 980 nm, 1200 nm, 1650 nm and 2200 nm, respectively. More importantly, the devices which have been laid aside for one month maintain their photoelectric response characteristics as well as before. So, our research opens a new path for silicon optical integrated in situ near-infrared (>1100 nm) detection. [Display omitted] • A wide spectrum detector based on silicon was fabricated by SILAR method. • The multidisperse system has a wider absorption spectrum. • The p-n junction were formed between PbS QDs and sIlicon nanowires. • PbS QDs greatly improved the absorption rate of infrared region. • The PbS QDs/Si-NWs device has good photoelectric response and excellent stability. [ABSTRACT FROM AUTHOR]

Li4Ti5O12 (LTO) is a promising anode material for lithium-ion batteries (LIBs) due to its stable reversibility, high-rate cyclability, and high operational potential. On the other hand, it suffers from poor electronic conductivity and low capacitance. To overcome these disadvantages, modification of the LTO surface is frequently undertaken. Considering this idea, the production of a biomass-derived carbon-coated LTO material (LTO/C) and its application as an anode in LIBs is described in this work. The carbon precursor was obtained from commercial carrot juice, which was degraded using microwaves. According to the UV studies, the carbon precursor revealed similar properties to carbon quantum dots. Then, it was deposited on LTO synthetized through a sol-gel method. The LTO/C electrode exhibited a high specific capacity of 211 mAhg−1 at 0.1 C. Capacity retention equal to 53% of the initial value was found for the charge–discharge rate increase from 0.1 C to 20 C. The excellent electrochemical performance of LTO/C was caused by the carbon coating, which provided (i) short diffusion pathways for the Li+ ions into the LTO structure and (ii) enhanced electronic conductivity. The obtained results indicated that biomass-derived carbon quantum dot-coated LTO can be considered as a promising anode for LIBs. [ABSTRACT FROM AUTHOR]

The voltammetric determination of amaranth is performed on the carbon paste electrode (CPE) surface that is enhanced using graphene quantum dots (GQD). The structure of ionic liquid (IL) may be used as an electrode modifier. Transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) analysis are used for characterising mentioned materials. The amaranth oxidation is performed by, chronoamperometry, and cyclic voltammetry (CV) as well as differential pulse voltammetry (DPV). It is done in a solution of blank phosphate buffer. Our suggested approach demonstrated proper linearity more than the range from 0.1 to 400.0 µM. In addition, the detection limit was lower 0.03 µM under the optimal conditions. The modified electrode shows appropriate selectivity for amaranth. In real samples, the rendered approach is used to amaranth determination, successfully. [ABSTRACT FROM AUTHOR]

The formation of PbTe quantum dots (QDs) in a crystalline CdTe host matrix is demonstrated by the annealing of a coherent, heteroepitaxial PbTe layer clad between CdTe layers. The resulting QDs have a centrosymmetric shape and they exhibit intense room-temperature mid-infrared photoluminescence due to an electron-hole pair recombination in the narrow-gap PbTe. The intense luminescence approves the high quality of the QD interfaces, between the sixfold coordinated rocksalt structure of PbTe and the fourfold coordinated zincblende structure of CdTe. To gain further insight into the structural interface properties, we compare quantitatively multislice simulations of HRTEM images with first-principles total-energy calculations in the repeated-slab approximation. The most drastic effect occurs at the electrostatically neutral (110) interface, where we find a lateral spatial offset between the two crystal halves due to rebonding across the interface. For the two polar (001) interfaces, significantly different lattice plane spacings are observed, depending on whether the polar CdTe (001) face is cation or anion-terminated. The agreement between the first-principles calculations and the HRTEM data is excellent. [ABSTRACT FROM AUTHOR]