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Incorporation of an efficient <i>β</i> -In <sub/>2</sub> S <sub/>3</sub> thin film as window material into CdTe photovoltaic devices
摘要： ABSTRACT. – Polycrystalline thin film CdS has been used as window material in photovoltaic solar cells. Its ideal band gap (2.45 eV), low resistivity and electron affinity made this material the most used in photovoltaic engineering; However, nowadays a cadmium free material with similar properties is necessary. β-In2S3 has shown adequate physical properties to be applied on CdTe, CIGS, CIS and CZTS solar cells. β-In2S3 thin films were grown by chemical bath deposition technique and thermally treated under different conditions. Their structural, optical, morphological and electrical properties were studied, and efficient cadmium free window layer was obtained and implemented on CdTe solar cells. The presented results are discussed.
关键词： Indium Sulfide,Novel window material.,Cadmium reduced solar cells
更新于2025-09-12 10:27:22
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The size dependence of optical properties in colloidal ZnxCd1-xS:Mn quantum dots in gelatin
摘要： Size-selected colloidal ZnxCd1-xS quantum dots were successfully prepared by aqueous synthesis in gelatin. Quantum dots with an average size of a few nanometers were obtained by changing the synthesis conditions such as the amount of precursors and temperature. Variation of the composition and size of particles leads to a change in the optical, in particular, luminescent characteristics of quantum dots. Estimation of particle sizes were performed by several methods based on X-Ray diffraction and optical data. The mechanisms of trap state photoluminescence in ZnxCd1-xS quantum dots are proposed. Models of increasing / decreasing the photoluminescence intensity depending on the composition and particle size are presented.
关键词： zinc sulfide,quantum dots,luminescence,quantum size effect,aqueous synthesis,cadmium sulfide
更新于2025-09-12 10:27:22
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Polydopamine nanospheres loaded with l-cysteine-coated cadmium sulfide quantum dots as photoelectrochemical signal amplifier for PSA detection
摘要： A sandwich-type photoelectrochemical (PEC) immunosensor was constructed for sensitive detection of prostate specific antigen (PSA). It was based on electrochemically reduced graphene oxide-TiO2 (ERGO-TiO2) as photoelectrochemical platform to immobilize capture antibody (Ab1). Then, quinone-rich polydopamine nanospheres (PDANS) loaded detection antibody (Ab2) and photocurrent signal label, L-cysteine-coated cadmium sulfide quantum dots (CdSQDs). ERGO-TiO2 displayed greatly improved photocurrent response to white light. CdSQDs conjugated with PDANS further amplified photocurrent signal because of the good conductivity of PDANS and ERGO. The increased photocurrent showed a linear correlation with PSA in the concentration range from 0.02 pg mL?1 to 200 ng mL?1 with the detection limit of 6.8 fg mL?1. It also revealed high selectivity and good stability.
关键词： Electrochemically reduced graphene oxide-TiO2,Polydopamine nanospheres,Photoelectrochemical immunosensor,L-cysteine-coated cadmium sulfide quantum dots,Prostate specific antigen
更新于2025-09-12 10:27:22
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Quantitative analysis of cadmium and zinc in algae using laser-induced breakdown spectroscopy
摘要： In the demand for renewable energy sources, algae are considered to have a good potential for biodiesel production. Fast detection of heavy metals in energetic algae is of vital importance for algal biomass and biodiesel production environment monitoring. This study aims to determine cadmium (Cd) and zinc (Zn) contents in algal pellets with laser-induced breakdown spectroscopy (LIBS) technology. Partial least squares (PLS) regression and extreme learning machine (ELM) were constructed after spectral preprocessing by standard normal variate transformation (SNV), multiplicative scatter correction (MSC) and Savitzky–Golay smoothing (SG). For univariate analysis, ELM models based on Cd II 226.45 nm and Zn II 206.19 nm of SNV preprocessed spectra achieved the best results for Cd and Zn content prediction respectively, with Rp, RMSEP and RPD values of 0.9866, 50.71 mg kg?1 and 6.95 for the former, and 0.9873, 30.08 mg kg?1 and 6.44 for the latter. Multivariate analysis of Cd based on the PLS model with global spectra achieved the best performance with Rc and Rp values of 0.9965 and 0.9972, RMSECV and RMSEP values of 25.57 mg kg?1 and 23.63 mg kg?1, and an RPD value as high as 13.27, showing the excellent robustness and effectiveness of the model for Cd detection. For Zn analysis, the best performance was achieved by the ELM model based on feature variables selected by regression coefficients, with Rc and Rp values of 0.9836 and 0.9920, RMSEC and RMSEP values of 34.25 mg kg?1 and 24.64 mg kg?1, and an RPD value of 7.87. The results indicated that the LIBS technique combined with appropriate preprocessing algorithms and multivariate chemometric methods could be a rapid and accurate way for quantitative analysis of Cd and Zn contents in algae and the aquatic environment.
关键词： laser-induced breakdown spectroscopy,quantitative analysis,chemometric methods,zinc,algae,cadmium
更新于2025-09-12 10:27:22
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Influences of buffer material and fabrication atmosphere on the electrical properties of CdTe solar cells
摘要： The electrical properties such as interface energy barriers, defect energy levels, and densities dictate the performance of thin film solar cells. Here, we show that these properties can be quantified in cadmium telluride (CdTe) thin‐film solar cells using admittance spectroscopy‐based techniques. Our results reveal that the electrical properties in CdTe thin‐film solar cells depend on both buffer material and the fabrication atmosphere. We find that only a negligible front contact barrier exists at the CdS/CdTe front junction regardless of the fabrication atmospheres, while an obvious front barriers are observed at the ZnMgO (ZMO)/CdTe junctions. Both CdS/CdTe and ZMO/CdTe solar cells exhibit back contact barrier. The energy level of defects is shallower in CdS/CdTe cells than in ZMO/CdTe cells. The fabrication atmosphere influences the electrical properties, i.e., an oxygen‐free atmosphere reduces the front and back barrier heights and lowers the energy level of defects. The results provide critical insights for understanding and optimizing the performance of CdTe thin‐film solar cells.
关键词： admittance spectroscopy,interface barriers,cadmium telluride,equivalent circuit,photovoltaic cells
更新于2025-09-11 14:15:04
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Ultrahighly Enhanced Performance of Single Cadmium Selenide Nanobelt by Plasmonic Gold Particles
摘要： Noble metal nanoparticles have been demonstrated by a huge application prospect for photodetector (PD) due to their unique and tunable optical properties. Herein, a simple strategy is presented by a combination of gold nanoparticles (Au NPs) and broadband photoresponse cadmium selenide nanobelts (CdSe NBs) to get ultrasensitive, broadband photoresponse (300–720 nm) and tunable photoresponse PD. Concretely, the Au NPs are fabricated on CdSe NBs via ion sputtering and annealing, and the morphology of Au NPs is systematically adjusted by simply tuning the sputter time from 60 to 140 s. Compared with the pure CdSe NB PD, the Au NPs hybrid CdSe NB PD exhibits a high responsivity, especially in the range of 525–575 nm with low light intensity (enhancement of (cid:3)2). The response time of the hybrid PD is (cid:1)2894% at 550 nm with 79.6 μW cm decreased substantially from 0.8 to 0.2 ms. More importantly, the hybrid PD possesses a tunable absorption in the range of 538–580 nm, which is bene?ted from tunable plasmon resonance of Au NPs. These results are con?rmed by the theoretical simulation. It is believed that this strategy offers new opportunities to design ultrasensitive, broadband spectra, and tunable wavelength PD.
关键词： cadmium selenide nanobelts,photodetectors,the discrete dipole approximation,surface plasmon resonances
更新于2025-09-11 14:15:04
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Degradation of Mg-doped zinc oxide buffer layers in thin film CdTe solar cells
摘要： Cadmium Sulphide is the conventional n-type bu?er layer used in thin ?lm Cadmium Telluride solar cells. It is well known that Cadmium Sulphide causes optical losses and sulphur di?uses into the absorber during high temperature activation. Sputter-deposited Mg-doped ZnO (MZO) has been shown to be an attractive bu?er layer for Cadmium Telluride solar cells due to its transparency and tuneable band gap. It is also stable to high temperature processing and avoids di?usion of elements into the cadmium telluride absorber during the cadmium chloride activation treatment. However, degradation is observed in solar cells incorporating MZO bu?er layers. Analysis of the MZO ?lm surface potential has revealed signi?cant ?uctuations in the thin ?lm work function once the layer is exposed to the atmosphere following deposition. These ?uctuations are attributed to the high reactivity to water vapour of the MgO contained in the MZO ?lms. This has been analysed using X-ray Photoelectron Spectroscopy to determine corresponding changes in the surface chemistry. The Zinc Oxide component is relatively stable, but the analysis shows that MgO forms a Mg(OH)2 layer on the MZO surface which forms a secondary barrier at the MZO/CdTe interface and/or at the interface between MZO and the Fluorine-doped SnO2. This a?ects the Fill Factor and as a consequence it degrades the conversion e?ciency.
关键词： Surface contamination,Degradation,Thin ?lm solar cells,Cadmium telluride,Magnesium-doped zinc oxide,Hydroxide,Bu?er
更新于2025-09-11 14:15:04
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Cadmium telluride quantum dots/graphene oxide/poly vinyl acetate (CdTe QDs/GO/PVAc) nanocomposite: a novel sensor for real time gamma radiation detection
摘要： The design of organic/inorganic nanoparticles hybrids provides the great potential for the fabrication of γ-ray sensor systems. Herein, structural and dosimetric properties of the gamma irradiated poly vinyl acetate (PVAc) doped with cadmium telluride quantum dots (CdTe QDs) and graphene oxide (GO) nanoflakes have been investigated. Thioglycolic acid (TGA) capped water-soluble CdTe QDs and (GO) nanoflakes are synthesized and characterized. Then, CdTe QDs/GO/PVAc sensors were formed by post-depositing CdTe and GO over polymer matrix. The photophysical interactions between nanoparticles and organic polymer have been investigated using ohmic contact detectors with two gold coated electrodes. Real time dose rate information of the sensors such as sensitivity, repeatability, and the linearity of dose rate response were assessed. A wider photoelectric response range and wider gamma harvesting range were observed in the resultant hybrid gamma sensor at a standard bias voltage with respect to non-hybrid CdTe QDs/PVAc sensors.
关键词： dosimetry,graphene oxide,poly vinyl acetate,radiation detection,Cadmium telluride quantum dots
更新于2025-09-11 14:15:04
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Solution-processed Zn <sub/><i>x</i> </sub> Cd <sub/> 1- <i>x</i> </sub> S Buffer Layers for Vapor Transport Deposited SnS Thin-film Solar Cells: Achieving High Open-circuit Voltage
摘要： As an alternative buffer material to CdS, ZnxCd1-xS buffer layers for vapor-transport-deposited SnS thin-film solar cells (TFSCs) were fabricated using the successive ionic layer adsorption and reaction (SILAR) method. Varying the Zn-to-Cd ratio resulted in a series of ZnxCd1-xS thin films with controllable bandgaps in the range of 2.40–3.65 eV. The influence of the Zn-to-Cd ratio on the cell performance was investigated in detail. The Zn0.34Cd0.66S buffer layer was found to be the optimal composition for SnS TFSCs, and a record open-circuit voltage (Voc) of 0.405 V was achieved with an efficiency of 3.72%, while the SILAR-CdS buffer layer rendered a Voc of 0.324 V. The improvement in Voc when using the Zn0.34Cd0.66S buffer layer was corroborated by the spike-type conduction band offset of 0.35 eV with the SnS absorber, as revealed by X-ray photoelectron spectroscopy analysis. In addition, minimized interfacial recombination at the SnS/Zn0.34Cd0.66S heterojunction was confirmed by temperature-dependent Voc analysis under illuminated conditions.
关键词： open-circuit voltage,successive ionic layer adsorption and reaction,thin-film solar cells,Tin monosulfide,buffer layer,zinc cadmium sulfide
更新于2025-09-11 14:15:04
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Temperature-Dependent Photoluminescence in CdTe/ZnTe Triple Quantum Dots
摘要： We studied the optical properties of CdTe/ZnTe quantum dots (QDs) in single, double, and triple QD structures by measuring the temperature-dependent photoluminescence (PL). On going from the single to the triple QD structures, the PL peak position of the QDs was blue shifted. This blue-shift was attributed to compressive strain imparted by the separation layers and to material intermixing. Temperature-dependent PL measurements of the triple QD structures showed that, as the temperature increased, the PL peak intensity for the 4.5-monolayer (ML) QDs decreased less than it did for the 3.0- and the 3.5-ML QDs. The activation energy of the 4.5-ML QDs in the triple QD structures was larger than that of the corresponding 4.5-ML QDs in the single QD structures. The reason for this is that, as the temperature increases, some carriers disappear due to non-radiative recombination, but many carriers in the 3.0- and the 3.5-ML QDs move to the 4.5-ML QDs in the triple QD structures, and those carriers then undergo radiative recombination.
关键词： Cadmium telluride,Photoluminescence,Triple quantum dots,Activation energy
更新于2025-09-11 14:15:04