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Robust Polymer Matrix Based on Isobutylene (Co)Polymers for Efficient Encapsulation of Colloidal Semiconductor Nanocrystals
摘要： We introduce new oxygen- and moisture-proof polymer matrices based on polyisobutylene (PIB) and its block copolymer with styrene (poly(styrene-block-isobutylene-block-styrene), PSt-b-PIB-b-PSt) for encapsulation of colloidal semiconductor nanocrystals. In order to prepare transparent and processable composites, we developed a special procedure of the nanocrystal surface engineering including ligand exchange of parental organic ligands to inorganic species followed by attachment of specially designed short-chain PIB functionalized with amino-group (PIB-NH2). The latter provides excellent compatibility of the particles with the polymer matrices. As colloidal nanocrystals, we chose CdSe nanoplatelets (NPLs), since they possess a large surface and thus are very sensitive to the environment, in particular in terms of their limited photostability. The encapsulation strategy is quite general and can be applied to a wide variety of semiconductor nanocrystals, as demonstrated on the example of PbS quantum dots. All obtained composites exhibited excellent photostability being tested in a focus of a powerful white-light source, as well as exceptional chemical stability in a strongly acidic media. We compared these properties of the new composites with those of widely used polyacrylate based materials, demonstrating the superiority of the former. The developed composites are of particular interest for application in optoelectronic devices, such as color-conversion light emitting diodes (LEDs), laser diodes, luminescent solar concentrators, etc.
关键词： photoluminescence,nanocrystals-in-polymer composites,lead sulfide quantum dots,semiconductor nanocrystals,isobutylene (co)polymers,cadmium selenide nanoplatelets,photostability,chemical stability
更新于2025-09-19 17:15:36
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Green Synthesis of Bismuth Sulfide Nanostructures with Tunable Morphologies and Robust Photoelectrochemical Performance
摘要： Manipulating the morphology of chalcogenide semiconductor crystals to tailor their shape- and size-dependent properties is much desired but remains a grand challenge. Herein, we for the first time develop a green, facile and surfactant-free hydrothermal approach for the synthesis of bismuth sulfide (Bi2S3) with highly tunable morphologies in H2WO4 aqueous solution. The H2WO4 is prone to balance the concentration of Bi3+ to S2- in aqueous solution, thus modulating the nucleation and epitaxial growth of Bi2S3. Specifically, in the presence of lower H2WO4 concentration, low number of Bi2S3 nuclei facilitates the preferred growth of nanorod structures along [001] direction, while the Bi-deficient, S-rich conditions in higher H2WO4 concentration give rise to Bi2S3 nanotubes, presumably due to the stronger interlayer interaction and preferred growth in [hk0] direction. The resulting Bi2S3 nanostructures exhibit broad absorption overlapping UV-Visible-NIR regions and red-shifted absorption edges owing to the increased S/Bi molar ratio in Bi2S3 lattices. The Bi2S3 nanorods with higher aspect ratio demonstrate an enhanced photocurrent response by virtue of the improved charge carrier mobility along [001] direction. Different from previous synthetic methodologies, this work details a facile, effective, and environmentally-benign protocol for the synthesis of Bi2S3 nanomaterials in the aqueous medium without any organic reagents. Noteworthy, the excellent and tailorable photoelectrochemical (PEC) performance endows these Bi2S3 nanostructures with vast potential in solar cell and photodetector applications.
关键词： Photoelectrochemical performance,Morphology control,Nanostructures,Green synthesis,Bismuth sulfide
更新于2025-09-19 17:15:36
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AVALIA??O DO PAPEL DO óXIDO DE GRAFENO (GO) NA GERA??O FOTOCATALíTICA DE HIDROGêNIO EM SISTEMAS BINáRIOS (GO-CdS) E TERNáRIOS (Pt-GO-CdS)
摘要： EVALUATION OF THE GRAPHENE OXIDE (GO) ROLE IN THE PHOTOCATALYTIC GENERATION OF HYDROGEN IN BINARY (GO-CdS) AND TERNARY (Pt-GO-CdS) SYSTEMS. Water splitting is a promising process to produce hydrogen from friendly feedstock and solar energy. In this work we have evaluated binary (GO-CdS) and ternary (Pt-GO-CdS) hybrid photocatalysts for hydrogen production assisted by visible light irradiation. Cadmium sulfide and composites with GO were prepared by sonochemical and thermal methods. GO addition took place by different strategies: during the synthesis or by mechanical mixture. A variety of configurations was tested and the best performance in hydrogen production among all materials was the ternary photocatalyst named Pt(GO/CdSTT), whose hydrogen production rate was 651 μmol gcat-1 h-1. Such material was obtained by thermal method with GO addition during the synthesis. Additionally, the XRD and Raman analyses have confirmed the GO photoreduction during photocatalytic hydrogen evolution.
关键词： graphene,water splitting,cadmium sulfide,visible light,hydrogen,photocatalysis
更新于2025-09-19 17:15:36
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Synthesis and structural characterization of microcrystalline Ga2S3 layers on a GaP semiconductor substrate
摘要： Gallium sulfide (Ga2S3) belongs to a group of wide bandgap semiconductors with interesting properties for infrared and nonlinear optics applications. Recent interest in Ga2S3 material focuses on the passivation of various semiconductor surfaces to enhance their electrical and optical properties. This work concerns the growth of microcrystalline gallium sulfide layers on semiconductive GaP substrates. The Ga2S3 layers were successfully obtained by reacting sulfur vapour with thin GaP semiconductor plates at two different temperatures: 450 °C and 600 °C. At the lower temperature (400 °C), no gallium sulfide layer formation was observed on the GaP substrate. Atomic force microscopy and Scanning Electron Microscopy were applied to illustrate the topography of the obtained Ga2S3 layers. Their thickness ranged from a few hundred nanometers to about 1–2 μm. The synthesized layers were structurally characterized by Raman spectroscopy. Raman polarization measurements were used to determine the crystalline phase of the Ga2S3 films. Raman tensor coefficients were obtained by fitting the most intensive Ga2S3 peaks to experimental data. The symmetry of the Raman peaks was in good agreement with the monoclinic Ga2S3 crystal phase.
关键词： Ga2S3 layers,Raman polarization measurements,Gallium (III) sulfide,Wide bandgap semiconductors
更新于2025-09-19 17:15:36
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A large Stokes shift, sequential, colorimetric fluorescent probe for sensing Cu2+/S2- and its applications
摘要： Copper ions (Cu2+) and sulfide (S2?) are important markers in many physiologies and pathological processes. In this work, a new near-infrared fluorescent probe 1 for colorimetric and sequential detection of Cu2+/S2? was designed and developed. The probe showed a rapid (less than 1 min), highly selective and sensitive response toward copper ions. Notably, the probe could also be applied to detect S2? through reversible formation-separation of complex 1-Cu2+ and CuS with a large Stokes shift of 234 nm. The detection limit for Cu2+ and S2? was found to be 1.8 × 10-8 M and 1.5 × 10-8 M, respectively. Furthermore, the binding stoichiometry between 1 and Cu2+ was found to be 1:1, the binding mode was also demonstrated using density functional theory (DFT) calculations and contrastive compound research. In addition, the probe was successfully applied in real water samples assay for the detection of Cu2+, and the strip papers experiments also showed that probe 1 can be used to detect Cu2+ and S2?.
关键词： DFT calculations,Colorimetric,Near-infrared,Sulfide,Large Stokes shift,Copper ions
更新于2025-09-19 17:15:36
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Dependence of pH on phase stability, optical and photoelectrical properties of SnS thin films
摘要： This study reports the effect of pH value of the reaction solution (5, 5.8 and 6.5) on growth rate of SnS films deposited by chemical bath deposition and their characteristics such as X-ray diffraction (XRD), surface morphology, phase stability, optical and photoelectrical. XRD analysis reveals that the films exhibit an orthorhombic structure with polycrystalline nature, in addition to the presence of the secondary phase Sn2S3 at pH 6.5. Field emission scanning electron microscopy observations show the formation of nanoflowers. Raman spectra manifest the presence of Sn2S3 phase, where its peak intensity gradually reduces until disappearance with decreasing pH value from 6.5 to 5. Furthermore, the enhancement in the dark current (conductivity) value of the thin films occurs with decreasing pH value, as well as increasing in the value of photocurrent under illumination of near-infrared 750 nm. Conversely, the sensitivity value decreased with decreasing pH. Moreover, the energy gap value ranges from 1.34 to 1.51 eV with increasing pH. The as-obtained results demonstrate the key role of pH in controlling SnS films characteristics to achieve high quality films for the applications of photodetectors and solar cells.
关键词： Phase,Raman,Tin sulfide,Sensitivity,Photodetector
更新于2025-09-19 17:15:36
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Enhanced solar cell performance of P3HT:PCBM by SnS nanoparticles
摘要： In this research, un- and zinc (Zn)-doped tin sulfide (SnS) nanoparticles (NPs) were synthesized by ultrasound method and added to the active layer of ITO/PEDOT:PSS/P3HT: PCBM/Al polymer solar cells (PSCs). The structural, optical, and electrical properties due to the influence of NPs on solar cell performance were investigated. The X-ray diffraction (XRD) patterns of the NPs indicates the formation of orthorhombic polycrystalline SnS. Field emission scanning electron microscopy (FESEM) images show spherical particles with size less than 100 nm for un- and Zn-doped SnS samples. Optical analysis of the cells shows a decrease in the band gap due to the presence of un- and Zn-doped SnS NPs. Photovoltaic characterization of the samples shows that by adding NPs to the polymer film, the device performance improves significantly compared to the absence of NPs. The presence of NPs with different concentrations and structural defects affects the electro-optical properties of the samples.
关键词： P3HT:PCBM,Polymer solar cells,Tin sulfide nanoparticles,Physical properties
更新于2025-09-19 17:13:59
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Surface passivation of a Cu(In,Ga)Se2 photovoltaic absorber using a thin indium sulfide layer
摘要： The present study demonstrates the surface passivation of Cu(In,Ga)Se2 (CIGS) photovoltaic absorbers using a thin In2S3 layer and its effect on the performance of the CIGS device. Two types of CIGS samples with different surface roughness values prepared by conventional selenization of metal precursors (2-step) and three-stage co-evaporation (3-stage) were used to determine the influence of In2S3 surface passivation on CIGS surface roughness to minimize recombination at the interface of the CIGS and buffer layers. Three types of buffer layers, i.e., In2S3, CdS single layers, and an In2S3/CdS double layer, were prepared by chemical bath deposition on bare and Mo-coated substrates as well as glass/Mo/CIGS samples. The phase formation and properties of the as-prepared buffer layers were analyzed by XRD, Raman, and UV–Vis–NIR techniques. The power conversion efficiency of the CIGS solar cells was enhanced significantly for the 2-step-processed CIGS (from 6.97% to 9.89%) and slightly for the 3-stage-processed CIGS (from 10.1% to 11.0%) when passivated with In2S3. Further, both the In2S3 surface passivated 2-step- and 3-stage-processed CIGS devices exhibited high quantum efficiencies in the wavelength range of 400–550 nm. Therefore, surface passivation with In2S3 could improve the performance of CIGS devices.
关键词： Chalcopyrite,Surface passivation,Indium sulfide,Hybrid buffer,Cu(In,Ga)Se2,Double buffer
更新于2025-09-19 17:13:59
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Indium sulfide based metal-semiconductor-metal ultraviolet-visible photodetector
摘要： In recent years, the photodetectors gained much attention due to their wide range of applications in industry, military, space and biological fields. In this work, the metal-semiconductor-metal (MSM) photodetector was fabricated using In2S3 thin films with Al interdigitated electrodes. The In2S3 thin films were prepared by co-evaporation technique with various thicknesses in the range 130–700 nm at a constant substrate temperature of 350 ?C. The structural, morphological, compositional, optical and electrical properties of In2S3 thin films were studied as a function of thickness. The energy band gap of films is found to be in the range 2.53–2.71 eV. I–V characteristics and photo response of photodetectors were recorded under UV and visible light illumination. The parameters of a photodetector such as photo sensitivity, responsivity and detectivity were calculated. The observed photo responsivity increases with increase of film thickness. The photo response of all photodetectors confirmed the stable and reproducible characteristics such as photo sensitivity, responsivity and detectivity.
关键词： Williamson-Hall plot,Co-evaporation,X-ray photoelectron spectroscopy,Ultraviolet-visible photodetector,Indium sulfide thin films
更新于2025-09-19 17:13:59
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High performance nBn detectors based on InGaAsSb bulk materials for short wavelength infrared detection
摘要： Objective: To investigate whether hydrogen sulfide (H2S) counteracts formaldehyde (FA)-induced cognitive defects and whether the underlying mechanism is involved in the upregulation of hippocampal brain-derived neurotrophic factor (BDNF) expression. Methods: The cognitive function of rats was evaluated by the Morris water maze (MWM) test and the novel object recognition test. The content of superoxide dismutase (SOD) and malondialdehyde (MDA) in the hippocampus were detected by enzyme-linked immunosorbent assay (ELISA). The neuronal apoptosis in the hippocampal CA1 region was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end (TUNEL) staining. The expression of the BDNF protein was detected by Western blot and immunohistochemistry. Results: We found that sodium hydrosulfide (NaHS, a donor of H2S) significantly reversed the impairment in the function of learning and memory in the MWM test and the novel objective recognition task induced by intracerebroventricular injection of FA. We also showed that NaHS significantly reduced the level of MDA, elevated the level of SOD, and decreased the amount of TUNEL-positive neurons in the hippocampus of FA-exposed rats. Moreover, NaHS markedly increased the expression of hippocampal BDNF in FA-exposed rats. Conclusions: H2S attenuates FA-induced dysfunction of cognition and the underlying mechanism is involved in the reduction of hippocampal oxidative damage and apoptosis as well as upregulation of hippocampal BDNF.
关键词： Cognitive defect,Oxidative stress,Brain-derived neurotrophic factor,Formaldehyde,Hydrogen sulfide,Apoptosis
更新于2025-09-19 17:13:59