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Study of (AgxCu1a??x)2ZnSn(S,Se)4 monograins synthesized by molten salt method for solar cell applications
摘要： The open circuit voltage (VOC) deficit of Cu2ZnSn(S,Se)4 (CZTSSe) kesterite solar cells is higher than that of the closely related Cu(InGa)Se2 solar cells. One of the most promising strategies to overcome the large VOC deficit of kesterite solar cells is by reducing the recombination losses through appropriate cation substitution. In fact, replacing totally or partially Zn or Cu by an element with larger covalent radius one can significantly reduce the concentration of I–II antisite defects in the bulk. In this study, an investigation of the impact of partial substitution of Cu by Ag in CZTSSe solid solution monograins is presented. A detailed photoluminescence study is conducted on Ag-incorporated CZTSSe monograins and a radiative recombination model is proposed. The composition and structural quality of the monograins in dependence of the added Ag amount are characterized using Energy Dispersive X-ray Spectroscopy and X-Ray Diffraction method, respectively. The Ag-incorporated CZTSSe monograin solar cells are characterized by temperature dependent current-voltage and electron beam induced current methods. It was found, that low Ag contents (x ≤ 0.02) in CZTSSe lead to higher solar cell device efficiencies.
关键词： Copper zinc tin sulfur selenide,Monograins,Electron beam induced current,Photoluminescence,Kesterite,Cations substituation
更新于2025-11-21 10:59:37
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Sulfur and Nitrogen Co-Doped Graphene Quantum Dots as a Fluorescent Quenching Probe for Highly Sensitive Detection toward Mercury Ions
摘要： Sulfur and nitrogen co-doped graphene quantum dots (SN-GQDs) were synthesized through an efficient infrared (IR)-assisted pyrolysis of glucose, urea, and ammonia sulfate at 260°C. These served as a highly selective probe for the sensing of Hg2+ ions in an aqueous solution. The IR technique can also prepare N-doped graphene quantum dots (N-GQDs), which have been compared with SN-GQDs for their fluorescence (FL) quenching sensitivities by Hg2+ ions. The FL intensities of both GQDs show decreasing functions of concentration of Hg2+ ions within the entire concentration ranges of 10 ppb?10 ppm. The sensitivity of SN-GQD is 4.23 times higher than that of N-GQD, based on the calculation of the Stern-Volmer equation. One inter-band gap structure of SN-GQDs for the detection of mercury ions is proposed. The S doping can coordinate with phenolic groups on the edge of SN-GQDs (i.e., the formation of (CxO)2Hg2+) and induce the cutting off or alleviation of photon injection paths, thereby leading to significant FL quenching. This work proves that SN-GQD offers sufficient sensitivity for probing the quality of drinking water to ensure that it contains less than 10 ppb of Hg2+ ions, as per the World Health Organization standard.
关键词： Fluorescence quenching,Nitrogen doping,Infrared-assisted heating,Graphene quantum dots,Sulfur doping,Mercury detection
更新于2025-11-19 16:56:42
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Photocatalytic degradation of sulfur black dye over Ce-TiO2 under UV irradiation: removal efficiency and identification of degraded species
摘要： TiO2 and Ce-TiO2 photocatalysts have been synthesized via sol–gel method and characterized by various techniques. Cerium incorporation maintains anatase phase formation, reduces the band gap energy, and inhibits the electron–hole recombination leading to a better photocatalytic response. Photocatalytic activities are explored on the degradation of sulfur black dye under UV light in the presence of H2O2. Photocatalytic reaction parameters have been assessed. Indeed, sulfur black dye color removal reached 92% at the optimal conditions in presence of 1% Ce-TiO2 catalyst. Identification of degradation products of sulfur black dye was achieved by LC/MS.
关键词： Ce-doped TiO2,Photodegradation,LC/MS analysis,Sulfur black dye
更新于2025-09-23 15:22:29
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Near-Infrared Light Triggered Sulfur Dioxide Gas Therapy of Cancer
摘要： The exploitation of gas therapy platforms holds great promise as a 'green' approach for selective cancer therapy, however, it is often associated with some challenges, such as uncontrolled or insufficient gas generation and unclear therapeutic mechanisms. In this work, a gas therapy approach based on near-infrared (NIR) light triggered sulfur dioxide (SO2) generation was developed, and the therapeutic mechanism as well as in vivo anti-tumor therapeutic efficacy was demonstrated. A SO2 prodrug-loaded rattle-structured upconversion@silica nanoparticles (RUCSNs) was constructed to enable high loading capacity without obvious leakage, and to convert NIR light into ultraviolet (UV) light so as to activate the prodrug for SO2 generation. In addition, SO2 prodrug-loaded RUCSNs showed high cell uptake, good biocompatibility, intracellular tracking ability, and high NIR light triggered cytotoxicity. Furthermore, the cytotoxic SO2 was found to induce cell apoptosis accompanied with the increase of intracellular reactive oxygen species (ROS) levels and the damage of nuclear DNA. Moreover, efficient inhibition of tumor growth was achieved, associated with significantly prolonged survival of mice. Such NIR light-triggered SO2 therapy may provide an effective strategy to stimulate further development of synergistic cancer therapy platforms.
关键词： upconversion nanoparticles (UCNPs),gas therapy,cancer therapy,near-infrared (NIR),sulfur dioxide (SO2)
更新于2025-09-23 15:22:29
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Measurement of Photosynthesis Using PAM Technology in a Purple Sulfur Bacterium <i>Thermochromatium tepidum</i> (Chromatiaceae)
摘要： We demonstrate that Blue-diode-based pulse amplitude modulation (PAM) technology can be used to measure the photosynthetic electron transport rate (ETR) of purple sulfur bacteria (Thermochromatium tepidum, Chromatiaceae). Previous studies showed that PAM technology could be used to estimate photosynthesis in purple nonsulfur bacteria and so PAM technology can be used to estimate photosynthesis of both kinds of purple photosynthetic bacteria. The absorptance of Thermochromatium films on glass fiber disks was measured and used to calculate actual ETR. ETR vs Irradiance curves fitted the waiting-in-line model (ETR = (ETRmax * E/Eopt) * exp (1-E/Eopt)). Yield (Y) was only 0.3–0.4. Thermochromatium saturates at 325 ± 13.8 μmol photons m?2 s?1 or ~15% sunlight and shows photoinhibition at high irradiances. A pond of Thermochromatium would exhibit classic surface inhibition. Photosynthesis is extremely low in the absence of an electron source: ETR increases in the presence of acetate (5 mol m?3) provided as an organic carbon source and also increases in the presence of sulfite (3 mol m?3) but not sulfide and is only marginally increased by the presence of Fe2?. Nonphotochemical quenching does occur in Thermochromatium but at very low levels compared to oxygenic photo-organisms or Rhodopseudomonads.
关键词： photosynthesis,PAM technology,photoinhibition,absorptance,Thermochromatium tepidum,purple sulfur bacteria,electron transport rate
更新于2025-09-23 15:22:29
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Sulfur-doped porous graphitic carbon nitride heterojunction hybrids for enhanced photocatalytic H2 evolution
摘要： Graphitic carbon nitride (g-C3N4) is considered as an attractive, efficient and newly generated photocatalyst material owing to its distinct properties such as metal free, suitable band gap and high physicochemical stability. Nevertheless, the photocatalytic activity of pure g-C3N4 was limited by the fast recombination rate of photoinduced electron–hole pairs and relatively low specific surface area. In this study, we provide a new prospect to overcome the problem by using another suitable precursor urea-assisted copolymerization with thiourea which is expected to optimize the process of thermal condensation, inhibit agglomeration and improve the specific surface area; meanwhile, the formed isotype heterogeneous junction effectively inhibits charge carrier recombination. The formed g-C3N4 isotype heterojunction photocatalyst manifested significant improvement photocatalytic hydrogen production than the single and pure g-C3N4 sample. This significant enhanced photocatalytic performance is mainly ascribed to inhibited recombination, enriched active site and enlarged specific surface area.
关键词： porous graphitic carbon nitride,heterojunction hybrids,photocatalytic H2 evolution,Sulfur-doped
更新于2025-09-23 15:21:21
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - On the Theory of a Pulse Microwave-Pumped Laser
摘要： A new construction of the microwave-pumped laser based on the light-pumping cell that uses radiation of sulfur vapor exposed to electromagnetic waves of the microwave band is described. Advantages of this design are the simple structure, high efficiency of the optical pumping cell, the possibility of cooling the pumping element, and easiness of modifying the emission spectrum of the optical pumping by changing the chemical composition of admixtures in the sulfur light-emitting cell. A mathematical tool for the simulation of the short-pulse operation of the microwave-pumped laser is proposed basing on the generalized wave equation solving for a regular transmission line with essentially nonlinear dispersion characteristic and substantial dissipation. Possible techniques for the numerical solving the generalized wave equation are discussed.
关键词： generalized wave equation,sulfur lamp,numerical simulation,pulse operation,microwave-pumped laser
更新于2025-09-23 15:21:01
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New Derivatization Reagent for Detection of free Thiol-groups in Metabolites and Proteins in Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging
摘要： Several diseases are associated with disturbed redox signaling and altered metabolism of sulfur-containing metabolites and proteins. Importantly, oxidative degradation of fresh-frozen tissues begins within the normal timescale of MALDI MSI sample preparation. As a result, analytical methods that preserve the redox state of the tissue are urgently needed for refined studies of the underlying mechanisms. Nevertheless, no derivatization strategy for free sulfhydryl groups in tissue is known for MALDI MSI. Here, we report the first derivatization reagent, (E)-2-cyano-N-(2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)ethyl)-3-(4-hydroxyphenyl)acrylamide (CHC-Mal), for selective detection of free thiols using MALDI MSI. We performed in-situ derivatization of free thiol groups from thiol-containing metabolites such as glutathione and cysteine and reduced proteins such as insulin and imaged their spatial distribution in porcine and mouse xenograft tissue. Derivatization of thiol-containing metabolites with CHC-Mal for MALDI MSI was also possible when using aged tissue in the presence of excess reducing agents. Importantly, CHC-Mal-derivatized low mass-metabolites could be detected without the use of a conventional MALDI matrix.
关键词： redox signaling,sulfur-containing metabolites,MALDI MSI,derivatization reagent,free thiol-groups
更新于2025-09-23 15:21:01
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Regulatory Preparation of N/S Doped Carbon Quantum Dots and Their Applications as Fe(III) Ion Sensors
摘要： The nitrogen-sulfur co-doped fluorescent carbon quantum dots (N/S-CQDs) were synthesized from sulfanilic acid. The fluorescence emission was independent of the excitation wavelength. In this experiment, the carbonization degree of the precursors was adjusted by solvent-thermal method to affect the sp2 conjugated dimension of CQDs, thus affecting the fluorescence performance of CQDs. They are well dispersed in water and ethanol, and have high selectivity for Fe3 +. The detection range is 0.025 ～ 0.4 mmol/L, and the detection limit is about 2.549 μmol/L. The CQDs prepared in this experiment emit light indirectly through the surface defect state. When CQDs is illuminated by light, the carriers generated by photons will emit light at a very fast speed due to the surface defect state, so the excited electrons in CQDs can be easily transferred to Fe3 +, making the surface of CQDs more complete, thus leading to the quenching of CQDs fluorescence.
关键词： Fe3 + sensor,Nitrogen and sulfur co-doping,carbon quantum dots,Fluorescence
更新于2025-09-23 15:21:01
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Case Series of Inappropriate Concentration of Intraocular Sulfur Hexafluoride
摘要： Due to high complexity, vitreoretinal surgery presents a higher number of patient safety incidents compared with other ophthalmic procedures. Intraocular gases are one of the most useful adjuncts to vitrectomy and surprisingly, surgeons commonly admit to having occasional problems with incorrect gas concentration. The aim of this study is to present a consecutive case series of patients with improper concentration of sulfur hexafluoride (SF6) applied during vitrectomy. Three patients underwent 27-gauge vitrectomy and at the end of surgery inappropriate dilution of 100% SF6 was administered. It was attributed to a calculation error, change in the gas supplier, or increased partial pressure of SF6 before dilution. Postoperatively, due to IOP increase, two eyes required intravitreal gas-air exchange. Subsequently, cataract surgery was performed in one eye with concomitant vitrectomy and silicone oil tamponade due to retinal detachment. To prevent such complications, we suggest using intraocular gases with great care, training of ophthalmic personnel, and prompting manufacturers to provide SF6 in a prepared concentration of 20%.
关键词： Intraocular pressure,Vitrectomy,Expandable gas,Intraocular tamponade,Sulfur hexafluoride
更新于2025-09-23 15:21:01