- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Influence of Sn2+ ion on structural, morphological and optical characteristics of Cd0.9a??xZn0.1SnxS (0a??a?¤a??xa??a?¤a??0.06) quantum dots
摘要： Water-soluble Cd0.9-xZn0.1SnxS (0 B x B 0.06) quantum dots were prepared by dual doping of Sn and Zn via chemical co-precipitation technique. XRD results con?rmed the cubic structure of CdS crystallites without generating any secondary peaks due to doping. TEM analysis revealed the structural information of the Sn-doped CdS host. The Sn substitution enhanced the particle size lightly. The surface morphological study revealed that the agglomeration of the samples was decreased. From UV–visible optical study, it was observed that the optical transmittance was suppressed owing to Sn substitution. Absorption peaks were blueshifted, and band gap values were widened due to incorporation of Sn. The strong PL emission peaks were received at 400 nm-1 and weak peaks near 490 nm-1. The peaks originated near the UV region were due to sulfur vacancies on the surface. EDX and FTIR studies con?rmed the presence of Sn in the prepared samples. Since the possibility of tailoring the band gap toward a high energy gap, these materials composition may be selected for optoelectronic device fabrication.
关键词： Blueshift,CdS QDs,Sn,Photoluminescence,Zn
更新于2025-09-23 15:21:01
-
Vital role of Ar ambient pressure in controlled properties of nanocrystalline CdS thin films
摘要： A report on the manipulation of structural, optical, and electrical properties of nanocrystalline CdS (ncCdS) thin films in the framework of varying Ar ambient pressure in pulsed laser deposition (PLD) is presented here. Increase in Ar ambient pressure results in reduction of crystallite size which in turns increases the structural imperfections and structural phase transformation of ncCdS thin films. The most significant observation here is the bleaching of multiphonon Raman modes (MRMs) particularly LO + 2E2, 2LO + 2E2, etc. in ncCdS thin films. An acute investigation on the reason of bleaching of LO + 2E2, 2LO + 2E2, etc. modes is carried out here and concluded that it is due to the fading of E2 mode with increasing Ar pressure as confirmed by low-frequency micro-Raman measurements. UV–visible absorption and photoluminescence spectroscopies are used to examine the optical properties like bandgap and possible electronic transitions in ncCdS thin films. Further, transport properties of ncCdS thin films are investigated using Hall measurement and I–V characteristics.
关键词： electrical properties,optical properties,Ar ambient pressure,structural properties,pulsed laser deposition,nanocrystalline CdS thin films
更新于2025-09-23 15:21:01
-
Thin-Film Solar Cells
摘要： Copper-indium-gallium-diselenide (CIGS) thin-film solar cells suffer from high recombination losses at the back contact and parasitic absorption in the front-contact layers. Dielectric passivation layers overcome these limitations and enable an efficient control over interface recombination, which becomes increasingly relevant as thin-film solar cells increase in efficiency and become thinner to reduce the consumption of precious resources. We present the optoelectronic and chemical interface properties of oxide-based passivation layers deposited by atomic layer deposition on CIGS. A suitable postdeposition annealing removes detrimental interface defects and leads to restructuring and oxidation of the CIGS surface. The optoelectronic interface properties are very similar for different passivation approaches, demonstrating that an efficient suppression of interface states is possible independent of the metal used in the passivating oxide. If aluminum oxide (Al2O3) is used as the passivation layer we confirm an additional field-effect passivation due to interface charges, resulting in an efficient interface passivation superior to that of a state-of-the-art cadmium-sulfide (CdS) buffer layer. Based on this chemical interface model we present a full-area rear-interface passivation layer without any contact patterning, resulting in a 1% absolute efficiency gain compared to a standard molybdenum back contact.
关键词： CIGS,CdS,atomic layer deposition,oxidation,thin-film solar cells,recombination losses,Al2O3,interface passivation
更新于2025-09-23 15:21:01
-
Structural Design and Pyroelectric Property of SnS/CdS Heterojunctions Contrived for Low-Temperature Visible Photodetectors
摘要： The traditional photodetectors based on photoelectric effect exhibit inferior response or even out of operation with the decrease of temperature. However, cryogenic visible light detection is increasingly demanded in deep space and polar exploration. Herein, a self-powered visible photodetector coupling pyroelectricity and photoelectricity to optimize the cryogenic detecting performance is designed in which hydrothermally grown CdS nanorod array is covered by SnS nanoflakes. The choice of SnS allows the detector with strong visible light absorption and great photoelectric conversion efficiency, while the CdS nanorod structure with pyroelectricity can effectively modulate the behavior of photogenerated carriers at low temperatures. It is found that the response characteristics of the photodetector are dominated by the combination of pyroelectric and photoelectric effects, which becomes more significant with the reduced temperature. Specifically, at 130 K temperature, the photoresponse current under 650 nm light is improved by 7.5 times as that at room temperature, while the ratio of pyroelectric current to photocurrent can be increased to 400%. Meanwhile, the responsivity and detectivity are as high as 10.4 mA W?1 and 3.56 × 1011 Jones, respectively. This work provides a promising approach to develop high-performance self-powered visible photodetectors with low-temperature operating capability.
关键词： pyroelectric,CdS,photodetectors,self-powered,low temperature
更新于2025-09-23 15:21:01
-
Layer-by-layer assembled synthesis of hollow yolk-shell CdSa??graphene nanocomposites and their high photocatalytic activity and photostability
摘要： Herein, we successfully synthesized, for the first time, a diameter of 340 nm hollow yolk-shell type CdS–graphene composite photocatalyst with a hollow core and an independent void space with 5~10 nm between hollow CdS core and graphene (GR) shell with the thickness of about 2 nm (denoted as hollow CdS@@GR), by the bottom-up method using the template-guided layer-by-layer self-assembly process. The formation mechanism of hollow CdS@@GR nanocomposites was proposed. Due to the unique hollow structure that can absorb more light, more dye, and catalyst molecules and the synergistic effect between hollow CdS core and GR shell with void space, hollow CdS@@GR showed enhanced photocatalytic performance. In addition, GR shell can effectively protect CdS from photocorrosion, and even after five repeated runs, the recycled nanocomposites exhibited superior stability. Moreover, we also proposed the possible photocatalytic mechanism of such nanostructures based on free radical capturing experiments and fluorescent probe technique. The design and fabrication of the hollow yolk-shell structured nanocomposites will provide a new potential route for other stable and efficient photocatalysts to satisfy versatile solar energy conversion.
关键词： Graphene,CdS,Hollow yolk-shell type,Stability,Nanocomposites,Semiconductors
更新于2025-09-23 15:21:01
-
Effect of substrate temperature on the properties of RF sputtered CdS thin films for solar cell applications
摘要： We report the effect of substrate temperature (25–300 °C) on the structural, optical and electrical properties of Cadmium Sulphide (CdS) thin films deposited onto glass substrate by Radio Frequency (RF) magnetron sputtering. The structural, morphological, optical and electrical properties of the films were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), UV–VIS-NIR spectroscopy and Hall Effect measurement respectively. The XRD studies showed that the films were polycrystalline with hexagonal wurtzite structure preferentially oriented along the (0 0 2) plane parallel to the substrate surface. The XRD data analysis further revealed the crystallite size of the nanocrystalline films i.e. 22–24 nm exhibiting the fact that crystallite size increased with increasing the substrate temperature. The FE-SEM images along with energy dispersive spectroscopy (EDS) studies confirmed the homogeneous, compact and pin-hole free surface morphology. The UV–VIS-NIR studies unveiled the optical transmittance in the range of 75–90% after 540 nm of the wavelength of light. The optical band gaps were found to be decreasing from 2.34 eV to 2.26 eV with increasing the substrate temperature. The films were characterized as n-type as evidenced by the Hall Effect measurement. The carrier mobility was found to be increasing gradually from 5.53 to 12.57 cm2/V·s by increasing the substrate temperature from room temperature to 300 °C due to the improvement of crystalline quality and grain size of the films. The results showed good optical and electrical properties of the films deposited at 300 °C which are suitable to use as window layer in thin film based solar cells.
关键词： CdS,UV–VIS-NIR,XRD,Hall effect measurement,Thin films,Substrate temperature,RF sputtering
更新于2025-09-23 15:21:01
-
Water hyacinth derived carbon quantum dots and g-C3N4 composites for sunlight driven photodegradation of 2,4-dichlorophenol
摘要： Carbon dots (CDs) were successfully derived from water hyacinth leaves and the binary composite was achieved by incorporating CDs with g-C3N4 through hydrothermal treatment. The average particle size of CDs was found to be 3.1 nm and a blue-green fluorescence was emitted under the UV light irradiation. Both of the composites loaded with 20 wt.% (20CDs/g-C3N4) and 40 wt.% (40CDs/g-C3N4) of CDs achieved the highest degradation efficiency of 2,4-dichlorophenol (2,4-DCP) with 1.7 times higher than that of pure g-C3N4. This work successfully improved the properties of g-C3N4 by elongating the lifetime of photogenerated electrons and widening the visible light response. Both of 20CDs/g-C3N4 and 40CDs/g-C3N4 recorded the highest photocatalytic performance in degrading 2,4-DCP with degradation rate constant of 0.0194, and 0.0186 min?1, respectively. This is contributed by the prolonged charge carrier lifetime in 20CDs/g-C3N4; good visible light absorption and high specific surface area in 40CDs/g-C3N4. For the scavenger test, hole (h+) and superoxide radical (·O2?) were acknowledged as the key active species in photocatalysis.
关键词： Carbon quantum dots,Water hyacinth,CDs/g-C3N4 composite,2,4-Dichlorophenol
更新于2025-09-23 15:21:01
-
Mn-doped CdS quantum dots as sensitizers in solar cells
摘要： CdS and di?erent concentrations of Mn+2 doped CdS quantum dots are synthesized via simple chemical method on poly-vinyl alcohol matrix. The doped and undoped CdS quantum dots are characterized by using UV–Vis absorption spectroscopy, X-ray di?raction, and energy dispersive X-ray spectroscopy to revel the changes in optical and structural properties due to Mn doping. The synthesized quantum dots were used as sensitizing layer on a ZnO thin ?lm solar cell and tested under arti?cial illumination condition to obtain the current density-voltage characteristics. A signi?cantly higher e?ciency of about 2.09% was obtained for Mn doped CdS quantum dots compared to that of 1% e?ciency in pure CdS quantum dot sensitized solar cell.
关键词： Mn doping,CdS quantum dots,QDSSC
更新于2025-09-23 15:21:01
-
A facile spray pyrolysis fabrication of Sm:CdS thin films for high-performance photodetector applications
摘要： Achievement of high-performance photodetectors based on CdS is a key field of research and challenge in the current scenario. Here, facile fabrication and characterization of novel samarium (1, 3 and 5 wt.% Sm)-doped CdS thin films for the photodetector applications have been demonstrated. The fabricated films show good crystallinity with crystallites size ranging 18–30 nm. The morphology and homogeneity of Sm-doping ingrown films were confirmed through scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX). Field emission SEM study reveals the low dimension nanograins formation and the films are free from voids and cracks. The effects of Sm-doping on linear and nonlinear optical properties of the fabricated thin films have been elucidated. The optical parameters such as refractive index, energy gap, susceptibilities were noticed to be reduced by Sm-doping in CdS thin films. An emission peak around 536 nm was observed in PL spectra of pure CdS which was found to be shifted and quenched by Sm-doping. Finally, the photodetector performance of the fabricated thin films has been investigated for 532 nm laser light. The photodetector based on the 1 wt.% Sm:CdS shows an improved performance (higher responsivity of 1.01 AW?1, higher detectivity of 2.21 × 1012 Jones, excellent photosensitivity of ～4.9 × 103, and very high external quantum efficiency (EQE) of 257 %) compared to pure CdS (responsivity of 0.213 AW?1, detectivity of 7.43 × 1011 Jones, photosensitivity of ～2.0 × 103, and EQE of 49.70 %). These results propose a much simpler route to achieve high-quality CdS films for photodetector applications.
关键词： Photoluminescence,Structural properties,CdS,Optical properties,Photodetector,Sm-doping,Thin films
更新于2025-09-23 15:21:01
-
Cascade Structured ZnO/TiO2/CdS quantum dot sensitized solar cell
摘要： Cascade structure of ZnO/TiO2/CdS quantum dot sensitized solar cell (QDSSC) using precursor solutions of CdS quantum dots having different concentrations such as 0.1 M, 0.2 M, 0.5 M and 0.8 M were synthesized on fluorine doped tin oxide (FTO) substrate, using the successive ionic layer absorption and reaction (SILAR) method. A polysulfide electrolyte was used as a redox mediator. The combination of ZnO/TiO2 used as a photoanode gives the best results and changes the mechanism of the QDSSC. The conventional Pt counter electrode was replaced by a low cost CuS counter electrode. Morphological and structural characterizations were carried out by field-emission scanning electron microscope (FESEM) & X-ray diffractometer, respectively. The optical characterizations were carried out by using ultraviolet–visible (UV–Vis) spectroscopy. Degree of porosity of prepared quantum dot (QD) sensitizers on TiO2/ZnO surface of different precursor concentrations 48.90%, 45.90%, 44.20% and 42.41% were observed. J-V characteristics and the performance of the prototype solar cell devices were evaluated by using a solar simulator, under illumination with an AM 1.5G spectrum having light intensity of 100 mWcm?2. The highest efficiency was obtained 2.44% at 0.1 M concentration and the lowest was 0.52% at 0.8 M concentration.
关键词： Quantum dot sensitized solar cell,ZnO/TiO2/CdS,Counter electrode
更新于2025-09-23 15:21:01