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ZnO@ZIF-8 inverse opal structure photoanode for efficient CdS/CdSe co-sensitized quantum dot solar cells
摘要： Photoanodes in quantum-dot-sensitized solar cells are essential to the process of light collection and charge transfer. In this paper, three-dimensional inverse opal (ZnO@ZIF-8 3D IO) photoanode is fabricated via a self-assembled opal template method. The synthesized photoanode has completely connected pores with extended diameter, thus promoting the permeability of QDs and electrolyte. Meanwhile, the light trapping ability and charge transfer process can be enhanced due to the slow photon and multi-scattering effect of the regularly interconnected macroporous array structure. ZIF-8 shell coated on the surface of ZnO IO not only provides high porosity but also serves as a protective passivation layer to reduce the carriers recombination occurred at the interfacial. In order to investigate the charge transport mechanism of ZnO @ ZIF-8 IO, cascaded CdS/CdSe quantum dots were used as sensitizers. Benefiting from the IO structure and ZIF-8 modification, the photoelectric conversion efficiency of solar cells based on ZnO@ZIF-8 IO can reach 1.75% (1.71 ± 0.04%), almost twice of that of the solar cells based on ZnO IO photoanode (0.81 ± 0.05%).
关键词： inverse opal structure,CdS/CdSe co-sensitized,ZnO@ZIF-8,photoanode,quantum dot solar cells
更新于2025-09-19 17:13:59
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Nonvolatile Resistive Switching Memory Device Employing CdSe/CdS Core/Shell Quantum Dots as an Electrode Modification Layer
摘要： Accompanied with great advantages in various fields of performance, memristors show huge potential in the next generation of mainstream storage devices. However, their random distribution of resistance switching voltage has always been one of the problems in applications. In this present work, a nonvolatile resistive switching memory device was proposed, which employed CdSe/CdS core/shell quantum dots (QDs) assembled as an electrode modification layer with the device configuration of Pt/CdSe-CdS QDs/TaOx/Ta. The device possesses multiple excellent resistance switching characteristics such as lower and more consistent set/reset threshold voltage and better endurance performance, which is considered as the effect of the electrode modification layer based CdSe/CdS core/shell QDs. A model with uneven QDs/Pt electrode interface was put forward to explain the different resistance switching behaviors, which may be beneficial to the development of existing research about memristors based on metal oxides and quantum dots.
关键词： Migration,Oxygen vacancy,Schottky interface,CdSe/CdS core/shell quantum dots,resistive switching
更新于2025-09-19 17:13:59
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The study on saturation current and ideality factor of CdTe solar cell based on CdS window layer deposited with hydrogen peroxide
摘要： By adding hydrogen peroxide (H2O2) to the solution, a more compact cadmium sulfide (CdS) film with larger optical band gap is fabricated by chemical bath deposition method. The oxidation of CdS is confirmed by the formation of cadmium sulfate (CdSO4) in the CdS window layer via x-ray photoelectron spectroscopy investigation. The analysis of quantum efficiency considering the alloy CdS1?yTey shows that the oxygenated CdS suppress the S-Te interdiffusion, which promotes the spectral response in short-wave range. Moreover, this oxygenated CdS layer promoted the conversion efficiency of the cadmium telluride (CdTe) based solar cell from11.2% to 14.0% due to the improvement of open-circuit voltage and the fill factor. The transport mechanisms of saturation current are evaluated by temperature dependent current–voltage curves. Results show that the oxygenated window layer reduces both the interfacial and bulk recombination, thus improves the ideality factor. The decrease of bulk recombination in depletion region is attributed to the fewer trap level induced from S-Te interdiffusion. The decrease of interfacial recombination is attributed to the larger optical band gap of oxygenated CdS, which results in a spike-like conduction band alignment at CdS/CdTe heterojunction.
关键词： saturation current,CBD,open-circuit voltage,ideality factor,CdS:O/CdTe heterojunction,hydrogen peroxide
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - CdCl <sub/>2</sub> Activation of the ZnTe:As Back Contact Layer in CdTe Thin Film Solar Cells, Employing a CdS Sacrificial Layer
摘要： Incorporating ZnTe:As back contact to CdTe thin film solar cells is an attractive alternative to Cu treated ZnTe back contacts, getting rid of Cu diffusion and subsequent long term stability issues. However, the Zn loss by the formation of volatile ZnCl2 during CdCl2 deposition heat treatment for the back-contact activation remains a challenge. The aim of this work is to develop an effective activation process for ZnTe:As back contacts, which is expected to improve CdTe solar cell efficiencies. To minimize Zn loss, a thin CdS sacrificial cap layer was evaluated which was deposited on ZnTe:As via MOCVD prior to the contact layer activation step.
关键词： ZnTe back contact,photovoltaic cells,CdS sacrificial layer,CdTe,Thin films
更新于2025-09-19 17:13:59
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Controlled Growth and Bandstructure Properties of One Dimensional Cadmium Sulfide Nanorods for Visible Photocatalytic Hydrogen Evolution Reaction
摘要： One dimensional (1D) metal sulfide nanostructures are one of the most promising materials for photocatalytic water splitting reactions to produce hydrogen (H2). However, tuning the nanostructural, optical, electrical and chemical properties of metal sulfides is a challenging task for the fabrication of highly efficient photocatalysts. Herein, 1D CdS nanorods (NRs) were synthesized by a facile and low-cost solvothermal method, in which reaction time played a significant role for increasing the length of CdS NRs from 100 nm to several micrometers. It is confirmed that as the length of CdS NR increases, the visible photocatalytic H2 evolution activity also increases and the CdS NR sample obtained at 18 hr. reaction time exhibited the highest H2 evolution activity of 206.07 μmol.g-1.h-1. The higher H2 evolution activity is explained by the improved optical absorption properties, enhanced electronic bandstructure and decreased electron-hole recombination rate.
关键词： photocatalytic H2 evolution,bandstructure,CdS nanorods,electron-hole recombination,solvothermal synthesis
更新于2025-09-19 17:13:59
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Characterization of PbS films deposited by successive ionic layer adsorption and reaction (SILAR) for CdS/PbS solar cells application
摘要： The properties of PbS thin films deposited by Successive Ionic Layer Adsorption and Reaction (SILAR) method were analyzed and applied in PbS/CdS heterojuction solar cells. In this study for n-type layer, cadmium sulfide thin films were deposited on transparent conductive oxide (ITO) substrates by Chemical Bath Deposition (CBD) technique followed by deposition of PbS film using different deposition cycles, 15, 20, 30, 40 and 60 to obtain different thicknesses from 90 nm to 658 nm. Morphological, structural and optical properties were investigated. The roughness of the PbS films were found to be in the range of 10–162 nm, depending on the number of cycles. The films of PbS present a band gap value of 0.6 eV. PbS/CdS heterojunctions were studied as solar cells, it was observed that 40 cycles PbS film has a greater photovoltaic conversion efficiency.
关键词： SILAR,PbS films,solar cells,PbS/CdS heterojuctions
更新于2025-09-19 17:13:59
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Supersandwich Nanowire/Quantum Dots Sensitization Structure-Based Photoelectrochemical a??Signal-Ona?? Platform for Ultrasensitive Detection of Thrombin
摘要： A new photoelectrochemical (PEC) “signal-on” sensing platform based on photoactive material Bi2O3-ZnO and CdS quantum dots (QDs) sensitizer were fabricated for ultrasensitive determination of thrombin by constructing supersandwich nanowires. The CdS/ZnO/Bi2O3 sensitization structure with excellent energy level arrangement remarkably improved photoelectric conversion efficiency due to efficient separation of electron-hole. Moreover, the DNA supersandwich nanowire is ingeniously synthesized in one step by simple dislocation hybridization, which could carry a large amount of sensitized material CdS QDs. More importantly, with Exo III-assisted multiple amplification, the proposed “signal-on” platform demonstrated a detection range of 10 fM to 1 μM with the detection limit of 1.41 fM for thrombin. Impressively, the PEC platform can successfully detect human serum samples with good accuracy. Above all, the CdS/ZnO/Bi2O3 sensitization photoelectric biosensing platform by using DNA nanowire in combination with Exo III-multiple amplification open new sensitized amplification paths for supersensitive biosensing and bioanalysis.
关键词： photoelectrochemical,CdS quantum dots,signal-on,thrombin detection,Bi2O3-ZnO,supersandwich nanowires,Exo III-assisted multiple amplification
更新于2025-09-19 17:13:59
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Green fluorescent carbon quantum dots functionalized with polyethyleneimine, and their application to aptamer-based determination of thrombin and ATP
摘要： Brightly fluorescent carbon quantum dots coated with polyethylenimine (PEI-CDs) were prepared using malic acid and PEI as the precursors. The PEI-CDs have a high quantum yield (41%) and green emission (peaking at 502 nm under 430 nm excitation), both of which are not affected by high ionic strength. The PEI-CDs have a positive charge at physiological pH values and can electrostatically bind aptamers with their negative charge. This is shown for aptamers binding thrombin or ATP. Binding of aptamers results in quenching of fluorescence. If thrombin or ATP are introduced, the respective aptamer will bind them, and the complex is then released from the PEI-CDs. Fluorescence increases in proportion to the analyte concentration. Under optimized conditions, thrombin and ATP can be sensitively and selectively detected by fluorometry with lower detection limits of 1.2 and 13 nM, respectively. The assay was successfully applied to the determination of thrombin and of ATP in spiked serum samples.
关键词： Aptamer sensor,Thrombin detection,Serum analysis,Green luminescent,PEI-CDs,Malic acid,Polyethylenimine,Fluorescence assay,ATP detection,Hydrothermal reaction
更新于2025-09-19 17:13:59
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CdS quantum dots embedded in PVP: Inorganic phosphate ion sensing in real sample and its antimicrobial activity
摘要： Polyvinyl-pyrrolidone capped spherical cadmium sulphide quantum dots (CdS-PVP QDs), 2–6 nm in size, were developed as a selective turn-on fluorescence nanosensor for monohydrogen phosphate ion (HPO4 2?) in aqueous medium. Fluorescence intensity of CdS-PVP QDs significantly increased with addition of HPO4 2? ions, whereas the other common inorganic ions had very little effect on the fluorescence intensity. The proposed sensor may be efficiently used for the detection of HPO4 2? ions at a low level of concentration up to 213 nM in real urine sample. Cell imaging study indicates that the CdS-PVP QDs are cell permeable and can detect the intracellular distribution of HPO4 2? ions under fluorescence microscope. The CdS-PVP QDs showed considerable activity against Staphylococcus aureus also.
关键词： Chemosensor,CdS,Antimicrobial activity,Cell image,Quantum dots,Phosphate ion sensing
更新于2025-09-19 17:13:59
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Evidence for Self-healing Benign Grain Boundaries and a Highly Defective Sb <sub/>2</sub> Se <sub/>3</sub> a??CdS Interfacial Layer in Sb <sub/>2</sub> Se <sub/>3</sub> Thin-Film Photovoltaics
摘要： The crystal structure of Sb2Se3 gives rise to unique properties that cannot otherwise be achieved with conventional thin-film photovoltaic materials, such as CdTe or Cu(In,Ga)Se2. It has previously been asserted that, grain boundaries can be made benign provided only the weak van der Waals forces between the (Sb4Se6)n ribbons are disrupted. Here it is shown that non-radiative recombination is suppressed even for grain boundaries cutting across the (Sb4Se6)n ribbons. This is due to a remarkable self-healing process whereby atoms at the grain boundary can relax to remove any electronic defect states within the band gap. Grain boundaries can however impede charge transport due to the fact that carriers have a higher mobility along the (Sb4Se6)n ribbons. Because of the ribbon misorientation certain grain boundaries can effectively block charge collection. Furthermore, it is shown that CdS is not a suitable emitter to partner Sb2Se3 due to Sb and Se inter-diffusion. As a result a highly defective Sb2Se3 interfacial layer is formed that potentially reduces device efficiency through interface recombination.
关键词： Sb2Se3-CdS interface,grain boundary relaxation,grain texture,Kirkendall voids,Sb2Se3 photovoltaics
更新于2025-09-19 17:13:59