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1D/3D Alloying Induced Phase Transition in Light Absorbers for Highly Efficient Sb <sub/>2</sub> Se <sub/>3</sub> Solar Cells
摘要： Simple binary inorganic antimony selenide (Sb2Se3) compound is attractive as a promising light absorber for low-cost and high-efficiency photovoltaic. The external quantum efficiencies of Sb2Se3 solar cells are now approaching the optical limit values, which are comparable with the traditional well-developed solar cells (such as Si, CuInGaSe2, CdTe, etc). However, the power conversion efficiency of the Sb2Se3 devices is constrained by the open-circuit voltage (VOC) deficit, due to the intrinsic high resistivity and low element-doping efficiency in such one-dimensional (1D) crystals. In this work, a highly conductive, 3D crystal-structure AgSbSe2 phase, formed by phase transition from low symmetry binary Sb2Se3, is introduced to control the doping density in the alloyed (Sb2Se3)x(AgSbSe2)1-x films by utilizing configurational entropy. Guided by this alloying concept, 1D-3D (Sb2Se3)x(AgSbSe2)1-x alloy films with tunable doping densities are obtained. As a consequence, a noticeable improvement in VOC by >18% is observed in solar cells based on (Sb2Se3)x(AgSbSe2)1-x alloy absorber layer, as compared to the reference cell with a pure Sb2Se3 absorber, leading to a high conversion efficiency of 7.8%. This alloying model provides a universal approach to control the photoelectrical properties for high-efficiency Sb2Se3-based solar cells.
关键词： thin film solar cells,light absorber,voltage deficit,antimony selenide,1D/3D alloying
更新于2025-09-23 15:19:57
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Impedimetric detection of Banana bunchy top virus using CdSe quantum dots for signal amplification
摘要： Banana bunchy top virus is considered to be the most economically destructive pathogens of banana that causes severe economic loss in banana plantations worldwide, including India. In this present study we have developed an improved electrochemical ELISA for detection of Banana bunchy top virus (BBTV). For enhanced and accurate detection we have used cadmium selenide (CdSe) quantum dots (QDs) as signal amplifiers. Experiments in this study were performed using primary antibody raised from recombinant coat protein of BBTV. CdSe QDs could significantly amplify the electrical signals in this assay and make the method appropriate for lab use. The result of electrical conduction showed the difference of impedance between the healthy and diseased sample of the order of ~ 100 Ω. The electrochemical ELISA could detect the virus in plant sap up to dilution of 1:25 as compared to 1:10 of conventional ELISA.
关键词： Faradic impedance spectroscopy,Cadmium selenide quantum dots (CdSe QDs),Banana bunchy top virus
更新于2025-09-23 15:19:57
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Controlled Synthesis of Au Nanocrystals-Metal Selenide Hybrid Nanostructures toward Plasmon-Enhanced Photoelectrochemical Energy Conversion
摘要： A simple method for the controllable synthesis of Au nanocrystals–metal selenide hybrid nanostructures via amino acid guiding strategy is proposed. The results show that the symmetric overgrowth mode of PbSe shells on Au nanorods can be precisely manipulated by only adjusting the initial concentration of Pb2+. The shape of Au–PbSe hybrids can evolve from dumbbell-like to yolk-shell. Interestingly, the plasmonic absorption enhancement could be tuned by the symmetry of these hybrid nanostructures. This provides an e?ective pathway for maneuvering plasmon-induced energy transfer in metal–semiconductor hybrids. In addition, the photoactivities of Au–PbSe nanorods sensitized TiO2 electrodes have been further evaluated. Owing to the synergism between e?ective plasmonic enhancement e?ect and e?cient interfacial charge transfer in these hybrid nanostructures, the Au–PbSe yolk-shell nanorods exhibit an outstanding photocurrent activity. Their photocurrent density is 4.38 times larger than that of Au–PbSe dumbbell-like nanorods under light irradiation at λ > 600 nm. As a versatile method, the proposed strategy can also be employed to synthesize other metal–selenide hybrid nanostructures (such as Au–CdSe, Au–Bi2Se3 and Au–CuSe).
关键词： surface plasmon resonance,morphology manipulation,gold-metal selenide,photoelectrochemical response,hollow hybrid nanostructure
更新于2025-09-23 15:19:57
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Photoinduced charge carrier dynamics in a ZnSe quantum dot-attached CdTe system
摘要： A new nanohybrid material is prepared by attaching CdTe nanoneedles (NNs) to surface-modified ZnSe quantum dots (QDs). The NNs and QDs are prepared by a colloidal synthesis method in an aqueous alkaline medium. The surface modification and the attachment of nanostructures are achieved by a bifunctional ligand 3-mercaptopropionic acid (3-MPA). The band gap of the ZnSe QDs is varied by controlling the size of the QDs in order to get the maximum overlap between the absorption band of the CdTe NNs and the emission band of the ZnSe QDs, which is a prerequisite for effective charge/energy transfer. The possibility of photoinduced charge transfer (PCT) and F?rster resonance energy transfer (FRET) from the donor (QDs) to the acceptor (NNs) has been assessed. Very fast (less than 800 ps) PCT and FRET from QDs to NNs occur because the emission band of QDs overlaps with the absorption band of NNs. The calculated large value of the overlapping integral, J(λ) ～4.5 × 1019 M?1 cm?1 nm4, of the donor and the acceptor bands proves the feasibility of energy transfer. These findings suggest that the ZnSe QDs can exchange photoinduced energy with the CdTe NNs effectively over a wide distance in a CdTe–ZnSe nanohybrid.
关键词： quantum dots,zinc selenide,F?rster resonance energy transfer,cadmium telluride,nanohybrid,charge transfer
更新于2025-09-23 15:19:57
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A Mixed-Dimensional van der Waals Heterostructure Photodetector
摘要： Van der Waals (vdW) heterostructures, integrated two-dimensional (2D) materials with variously functional materials, provide a distinctive platform for next-generation optoelectronics with unique flexibility and high performance. However, exploring the vdW heterostructures combined with strongly correlated electronic materials is hitherto rare. Herein, a novel temperature-sensitive photodetector based on the GaSe/VO2 mixed-dimensional vdW heterostructure is discovered. Compared with previous devices, our photodetector exhibits excellently enhanced performance, with external quantum efficiency up to 109.6 % and the highest responsivity (358.1 mA?W?1) under a 405 nm laser. Interestingly, we show that the heterostructure overcomes the limitation of a single material under the interaction between VO2 with GaSe, where photoresponse is highly sensitive to temperature and can be further shut at the critical value. The metal-insulator transition of VO2, which controls the peculiar band-structure evolution across the heterointerface, is demonstrated to manipulate the photoresponse variation. This study enables us to elucidate the method of manipulating 2D materials by strongly correlated electronic materials, paving the way for developing the high-performance and special optoelectronic application.
关键词： gallinum selenide,Vanadium dioxide,MIT-controlled photoresponse,mixed-dimensional van der Waals heterostructure,band engineering
更新于2025-09-23 15:19:57
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[IEEE 2018 IEEE 13th Nanotechnology Materials and Devices Conference (NMDC) - Portland, OR, USA (2018.10.14-2018.10.17)] 2018 IEEE 13th Nanotechnology Materials and Devices Conference (NMDC) - Magnetic Characterization of Cobalt Selenide and Nickel Selenide Thin Films
摘要： Transition metal dichalcogenides (TMDCs) are a family of materials whose crystalline structure consists of a layer of transition metal atoms sandwiched between 2 layers of chalcogenide atoms. Some of these materials can be grown in 2D hexagonal phase and show tunability of their electrical and magnetic properties based on layer thickness. One aspect of these materials that has received little attention is their magnetic properties. Hence, we have investigated magnetic properties of CoSe and NiSe their heterostructure. The reason for choosing these intrinsically ferromagnetic transition metal atoms based TMCs was to examine how reduction from the bulk to 2D films would influence the magnetic activity of these samples. In order to produce large area films, we have employed atomic layer deposition (ALD) for growth of uniform, few layer-thick films. First the composition and crystal structure of these films are characterized, and then their magnetic properties analyzed. We have found that thin films of both these materials show mostly paramagnetic behavior.
关键词： cobalt selenide,magnetic properties,Transition metal chalcogenides,thin film,nickel selenide
更新于2025-09-19 17:15:36
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Colloidal Synthesis of Bulk-Bandgap Lead Selenide Nanocrystals
摘要： Lead selenide quantum dots (QDs) are low-bandgap IV-VI semiconducting nanomaterials that have been studied for a variety of applications. Their preparation using colloidal methods can create small spherical to larger cubic nanocrystals, with an upper limit of ～17 nm reported to date. Here we describe methods for preparing cubic PbSe nanocrystals over a 20–40 nm size range using a two-step procedure. Specifically, ～10 nm PbSe QDs are generated using the rapid injection method, the products from which are overcoated with additional lead and selenium precursors. The use of two lead reagents were studied; lead oleate resulted in a maximum of 20 nm cubes, while more reactive lead hexyldecanoate resulted in much larger nanomaterials with bulk bandgaps. However, PbSe samples prepared with lead hexyldecanoate also contained agglomerates. Special care must be taken when characterizing larger strained nanomaterials with X-ray powder diffraction, for which the Scherrer equation is inadequate. A more rigorous approach using the Williamson–Hall method provides characterizations that are consistent with electron microscopy analysis.
关键词： lead selenide,nanomaterials,conductivity,semiconductor,quantum dots
更新于2025-09-19 17:15:36
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Size effect-enhanced thermoelectric properties of nanoscale Cu2-xSe
摘要： As a promising thermoelectric material, copper selenides have attracted the interest of researchers owing to their low cost, abundance in earth, environmental friendliness, and low thermal conductivity. In this study, copper selenide (Cu2-xSe) powders with controllable sizes from nanoscale to mesoscale were obtained by a facile one-pot solvothermal method. After treatment with spark plasma sintering, the nanoscale Cu2-xSe pellets exhibited excellent thermoelectric properties such as sharply reduced thermal conductivity and enhanced Seebeck coefficient as well as a suppressed electrical conductivity. The figure of merit (ZT) of the nanoscale Cu2-xSe reached up to ~1.51 at 873 K, which is about 2.67 times higher than that of the meso-Cu2-xSe. This study confirms that thermoelectric properties can be enhanced by the size effect.
关键词： size effect,solvothermal method,thermoelectric property,Copper selenide,nanoscale
更新于2025-09-19 17:15:36
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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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A Highly Efficient and Durable Water Splitting System: Platinum Sub-Nanoclusters Functionalized Nickel Iron Layered Double Hydroxides as the Cathode and Hierarchical Nickel Iron Selenides as the Anode
摘要： Developing cost-efficient and effective catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) remains a great challenge for the applications of high-efficiency water electrolyzers. In this work, we design a highly efficient and durable water splitting system in an alkaline solution, of which the platinum (Pt) sub-nanoclusters (average size: 0.59 nm) functionalized nickel iron layered double hydroxide nanosheets on carbon fiber cloth (Pt-NiFe LDH/CC) serve as the cathode and the hierarchical (Ni0.77Fe0.23)Se2 nanosheets on CC ((Ni0.77Fe0.23)Se2/CC) act as the anode. For the HER, the three-dimensional (3D) Pt-NiFe LDH/CC electrode with an ultralow Pt content (1.56 wt%) drives a current density of 10 mA cm-2 under an ultralow overpotential of 28 mV. For the OER, the edge-rich (Ni0.77Fe0.23)Se2/CC electrode displays a current density of 10 mA cm?2 under a small overpotential of 228 mV, and the Tafel slope is as low as 69 mV dec?1. More importantly, the assembled Pt-NiFe LDH/CC || (Ni0.77Fe0.23)Se2/CC water splitting electrolyzer exhibits a high current density of 30 mA cm?2 at a low cell voltage of 1.57 V, which is superior than that of electrolyzer assembled by the commercial 20 wt% Pt/C and RuO2 electrodes (30 mA cm?2 at 1.62 V). Additionally, the Pt-NiFe LDH/CC || (Ni0.77Fe0.23)Se2/CC electrolyzer displays excellent stability over 40 hours even at a high current density of 50 mA cm?2, which shows a great potential in the practical applications of full water splitting.
关键词： Hydrogen Evolution Reaction,Platinum Sub-Nanoclusters,Oxygen Evolution Reaction,NiFe Layered Double Hydroxide,Porous NiFe Selenide
更新于2025-09-19 17:15:36