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Cuprous Sulfide for Different Laser Pulse Generation: Q-Switching and Mode-Locking
摘要： As a new type of copper-based chalcogenide two-dimensional nanomaterial, cuprous sulfide (Cu2S) has attracted much attention due to its unique band structure and optical properties. In this paper, all-fiber ring laser at the 1.53 μm regime with two kinds of Cu2S saturable absorber devices is demonstrated. The self-started Q-switched pulse with a central wavelength of 1530 nm was obtained for the first time by using Cu2S deposited on the fiber jumper as SA. When the tapered fibers deposited with Cu2S are used to replace the jumpers in the cavity, it can be found that the loss is significantly reduced and a mode-locked pulse with a pulse width of 896 fs has been achieved via evanescent field interaction. This experiment further enriches the application of Cu2S nanosheets in pulsed lasers and promotes the development and application of metal sulfides in nonlinear optics and ultrafast photonics.
关键词： saturable absorber,cuprous sulfide,mode-locking,Q-switching,ultrafast photonics,Cu2S,nonlinear optics
更新于2025-09-23 15:19:57
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Laser-Generated BiVO4 Colloidal Particles with Tailoring Size and Native Oxygen Defect for Highly Efficient Gas Sensing
摘要： To alleviate the poor sensing performance of BiVO4, developing new strategies for the fabrication of unique device with improved sensing properties is very necessary and has great practical significance. In this work, size-tailored and uniform black BiVO4 colloids with abundant oxygen vacancy were synthesized by a unique method of pulsed laser irradiation of colloidal nanoparticles (PLICN). The corresponding laser irradiation effects on the sensing properties are comparatively investigated. The results indicate that the BiVO4 nanospheres with average size of 50 nm shows best sensing properties with high sensitivity, superior selectivity, low detection limit (44 ppb) to H2S at low working temperature (75 oC). Its sensing response is over 4 times higher when comparing with that of the raw material. Further investigation manifests that laser irradiation could induce quantity of the oxygen vacancy and decrease the resistance of the sensing device, which is mainly responsible for the enhanced sensing performance. Moreover, the density functional theories (DFT) calculations suggest that the oxygen vacancies can greatly decrease the surface absorption energy with enhanced H2S absorption capability on BiVO4 surface and lower the bader charger transfer from the absorbed H2S molecules to the BiVO4, thus enabling the implementation for the enhanced gas-sensing properties.
关键词： Pulsed laser irradiation,Hydrogen sulfide,Bismuth vanadate,Nanosphere,Gas sensor
更新于2025-09-23 15:19:57
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Ultrahigh resolution spectroscopy for dimethyl sulfide at the ??1- and ??8-bands by a distributed feedback interband cascade laser
摘要： The ultrahigh-resolution, air-broadened mid-infrared absorption spectrum of dimethyl sulfide (DMS) was recorded in the spectral region of 2994.17–2999.03 cm?1, where the strong ν1-/ν8-bands are located. Benefitting from the tunable laser absorption spectrometry with a distributed feedback interband cascade laser, the spectral resolution achieved 5.69 × 10?6 cm?1. The recorded spectra of DMS are very close to that in the Pacific Northwest National Laboratory (PNNL) database, however it has a much lower absorbance uncertainty of 0.38%. And the maximum relative difference of the full width at half maximum and the integrated area of spectral peaks between the recorded spectra and the PNNL data are as large as 16.7% and 27.9%, respectively, which could mainly come from the difference of the spectral resolution. The more accurate reference spectrum is hopeful to be applied to absolute measurement and remote sensing for gaseous DMS.
关键词： Tunable laser absorption spectroscopy (TLAS),Dimethyl sulfide (DMS),Ultrahigh-resolution spectrum,Interband cascade laser (ICL),Mid-infrared
更新于2025-09-23 15:19:57
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Synergy of PVP and ethanol to synthesize Ni3S4 quantum dots for high-performance asymmetric supercapacitors
摘要： Ni3S4 quantum dots (QDs) have great potential for supercapacitors due to their unique quantum effects, high specific surface area, high water solubility and good stability, but the current preparation process is cumbersome and toxic. Here, we highlighted a facile and environmental-friendly synthesis of Ni3S4 QDs for the first time by virtue of the synergy of polyvinylpyrrolidone (PVP) and ethanol. The synergistic mechanism was revealed by using XRD to investigate the effect of synthesis solvent. When QDs was used as a supercapacitor electrode material, it exhibited excellent electrochemical properties, and the specific capacitance at 1 A g-1 was 1440 F g-1. In addition, Ni3S4 QDs and activated carbon (AC) are assembled into Ni3S4 QDs//AC asymmetric supercapacitor (ASC), which delivered the maximum energy density of 60.4 Wh kg-1. This work provides new ideas for the preparation of QDs and opens up new concepts for the synthesis of nickel sulfide.
关键词： supercapacitors,nickel sulfide,energy storage,environment friendly,PVP,quantum dots
更新于2025-09-23 15:19:57
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Enhanced Power Conversion Efficiency of Dye-Sensitized Solar Cells by Band Edge Shift of TiO2 Photoanode
摘要： By simple soaking titanium dioxide (TiO2) films in an aqueous Na2S solution, we could prepare surface-modified photoanodes for application to dye-sensitized solar cells (DSSCs). An improvement in both the open-circuit voltage (Voc) and the fill factor (FF) was observed in the DSSC with the 5 min-soaked photoanode, compared with those of the control cell without any modification. The UV–visible absorbance spectra, UPS valence band spectra, and dark current measurements revealed that the Na2S modification led to the formation of anions on the TiO2 surface, and thereby shifted the conduction band edge of TiO2 in the negative (upward) direction, inducing an increase of 29 mV in the Voc. It was also found that the increased FF value in the surface-treated device was attributed to an elevation in the shunt resistance.
关键词： surface modification,conduction band edge shift,dye-sensitized solar cell,sodium sulfide
更新于2025-09-23 15:19:57
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Direct fabrication of Cd–In–S alloy quantum dots thin films
摘要： In this article, a new simple one-step process to fabricate Cd–In–S luminescent quantum dot thin films (QDTFs) is provided. Metal sulfide precursor solutions were manufactured by directly adding a certain amount of butylamine and carbon disulfide in the ethanol solution followed by dissolving Cd(OH)2 and In(OH)3 powder. Cd–In–S luminescent QDTFs can be obtained by mixing Cd and In precursor solutions and then spinning on a cover slip and annealing on a hot plate at 190 °C under air atmosphere directly without complicated synthesis method. By changing the sintering parameters including the temperature, time and ratios of (Cd+In)/ligand, the Cd–In–S luminescent QDTFs covering the entire visible light wavelength from 470 to 628 nm can be obtained. The Cd–In–S luminescent QDTFs exhibited remarkable optical properties and has potential application in solar cell and light emitting diode, with the photoluminescence quantum yield of up to 36.5%.
关键词： metal sulfide precursor solution approach,Cd–In–S,Quantum dots thin films
更新于2025-09-23 15:19:57
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Dielectric Measurements of Polymer Composite Based on CdS Quantum Dots in Low Density Polyethylene at Microwave Frequencies
摘要： CdS nanoparticles (NPs) as quantum dots (QDs) added into low density polyethylene (LDPE) can significantly change the MW dielectric properties of the composites. Introducing into the matrix of low density polyethylene CdS QDs increase the dielectric constant of more than twice. CdS QDs with concentration of 5 wt % to 20 wt % were prepared by the method of high-speed thermal decomposition. The size of CdS nanoparticles ranged from 2 nm to 7 nm. Experimental samples based on polymer-based nanocomposite in the form of thick films with a thickness of 80 to 100 microns were prepared by thermocompression. Complex dielectric permittivity of thick film samples was measured by T/R method from 2 to 8 GHz at room temperature (25°C). For samples with 20 wt % CdS NPs size effect was found. The change of dielectric properties of polymer composite materials is associated with the size of QDs. The dielectric constant and dielectric loss increases with decreasing size of the quantum dots. It is shown that the highest mean value of the dielectric constant and dielectric loss at a frequency range of 5 GHz to 8 GHz for cadmium sulfide nanoparticles with size of 4 nm were 12 and 189 dB/m, respectively. For QDs with ones of 6 nm average dielectric constant and dielectric loss were 5.8 and 134 dB/m, respectively. The effective dielectric constant and dielectric losses in the microwave range can be changed by CdS QDs of different sizes what consequently increases the possibility of using polymer nanocomposites as core elements of the microwave band-pass filters for various purposes.
关键词： quantum dot,cadmium sulfide,polymer composite,filled polymer,MW dielectric properties,low density polyethylene,composites
更新于2025-09-23 15:19:57
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5, 10, 15, 20-tetrakis-(4-methoxyphenyl) porphyrin film/K+ ion-exchanged optical waveguide gas sensor
摘要： Optical waveguide (OWG) sensors are widely used in gas detection, and sensitive materials are the key factors affecting sensor performance. Herein, we report on a 5,10,15,20-tetrakis-(4-methoxyphenyl) porphyrin (TMP) deposited optical wave guide (OWG) sensor. The porphyrin solutions with different acidity were deposited on a K+-ion exchanged glass OWG surface by spin coating, to fabricate porphyrin film-coated OWG gas sensing devices. The effects of pH values of the porphyrin solution used to prepare the sensitive film on the sensing properties of these devices were investigated. The gas sensitive performances of these devices in response to analytes were compared. Among them, the sensing devices fabricated using original and acidic solutions of porphyrin exhibited significant responses to sulfide gases and ethanediamine, respectively. The sensing device prepared using an acidic solution has a good response to ethanediamine gas (response and recovery times of the sensor for 1 ppm of EDA (ΔI = 48) are 13 and 38 s, respectively). The RSD of the output light intensity is ± 2.84, the signal to noise ratio (S/N) is 5.6. The device prepared using the original solution has an excellent response to sulfide gases (H2S, SO2), and can detect low concentration levels (ppm) of sulfide gases. These sensing devices thus have the potential to be used in food quality testing and environmental monitoring.
关键词： Aggregation,Ethanediamine,5,10,15,20-tetrakis-(4-methoxyphenyl) porphyrin,Optical waveguide gas sensor,Sulfide gases
更新于2025-09-23 15:19:57
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All Antimony Chalcogenide Tandem Solar Cell
摘要： We demonstrate a proof-of-concept tandem solar cell using Sb2S3 and Sb2Se3 as top and bottom cell absorber materials. The band gaps of Sb2S3 and Sb2Se3 are 1.74 and 1.22 eV, perfectly satisfying the requirement of tandem solar cells. The application of few-layer graphene enables high transmittance and excellent interfacial contact in the top sub-cell. By controlling the thickness of the top cell for maximizing the spectral application, the tandem device delivers a power conversion efficiency of the 7.93%, which outperforms the individually optimized top cell (5.58%) and bottom cell (6.50%). Mechanistical investigation shows that the tandem device is able to make up voltage loss in the sub-cells, which is a critical concern in the current antimony chalcogenide solar cells. This study provides an alternative approach to enhancing the energy conversion efficiency of antimony selenosulfide.
关键词： antimony sulfide,energy conversion,semi-transparent electrode,tandem solar cell,antimony selenide
更新于2025-09-23 15:19:57
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Laser-induced graphene hybrid photoelectrode for enhanced photoelectrochemical detection of glucose
摘要： The combination of electrocatalyst with semiconductor light-absorber is of great importance to increase the efficiency of photoelectrochemical (PEC) glucose detection. Here, in-situ and synchronous fabrication of Ni-based electrocatalyst (NiEC) and CdS semiconductor in laser-induced graphene (LIG) on indium?tin oxide glass is demonstrated via a one-step laser-induced solid phase transition. A series of component and structural characterizations suggest that the laser-induced NiEC uniformly disperses in the hybrid nanocomposite and exists mainly in the form of Ni0 and NiO state. Moreover, both electrochemical and PEC investigations confirm that the as-prepared hybrid photoelectrode exhibits excellent photoelectrocatalytic ability towards glucose, which is not only attributed to the strong synergistic interaction between CdS and NiEC, but also benefited from the high conductivity as well as 3D macroporous configuration of the simultaneously formed LIG, providing the key factor to achieve sensitive non-enzymatic PEC glucose sensors. Therefore, the laser-induced hybrid photoelectrode is then applied to the PEC detection of glucose, and a low detection limit of 0.4 μM is obtained with good stability, reproducibility, and selectivity. This study provides a promising paradigm for the facile and binder-free fabrication of electrocatalyst?semiconductor?graphene hybrid photoelectrode, which will find potential applications in sensitive PEC biosensing for a broad range of analytes.
关键词： nickel electrocatalyst,hybrid nanocomposite,cadmium sulfide,photoelectrochemical sensing,laser-induced graphene,glucose
更新于2025-09-23 15:19:57