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Cu Nanoparticle Array-Mediated III-V/Si Integration: Application in Series-Connected Tandem Solar Cells
摘要： The integration of III-V materials with crystalline Si (c-Si) is a promising pathway to design high-performance optoelectronic devices, including solar cells. We have previously reported high-efficiency III-V/Si tandem cells using our unique semiconductor bonding technique, termed smart stack. In the conventional smart stack cells, Pd nanoparticle (NP) arrays have been commonly employed as bonding mediators between III-V and c-Si; however, from an economical point of view, the use of other low-cost metals would be preferable. Therefore, this study focused on the possibility of Cu. A polystyrene-block-poly-2-vinylpyridine (PS-b-P2VP)-based block copolymer was utilized to prepare Cu NP arrays. Desired Cu NP arrays were achieved by starting with self-assembled PS-b-P2VP micelles preloaded with Cu2+ ions. Satisfying bonding properties (low-resistance interfaces) were confirmed when GaAs subcells were stacked on the Cu NP arrays formed on native oxide-removed c-Si subcells. Conversion efficiencies up to 25.9% have been demonstrated with triple-junction structures consisting of InGaP/GaAs top and c-Si bottom subcells. The long-term reliability of Cu NP array-mediated smart stack cells were also verified by the thermal cycle and damp heat tests. Hence, we have successfully confirmed that not only Pd but also Cu is available to realize high-efficiency smart stack cells.
关键词： III-V,Copper,block copolymer,solar cell,tandem,nanoparticle,silicon,self-assembly
更新于2025-09-23 15:19:57
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Developing highly crystalline, single-phase and copper-poor Cu2ZnSnSe4 nanoparticles for solar cell application
摘要： In this study, we report the synthesis of Cu(Zn,Sn)Se2 (CZTSe) nanoparticles by hot-injection method for application to the absorber layer in solar cells. The composition of elements in the CZTSe nanoparticles depends mainly on the injection speed of the Se precursor. By controlling the injection speed, we obtained complete single-phase CZTSe nanoparticles with high crystallinity and copper-poor composition. The nanoparticle diameter mainly ranged from ~ 7 nm to 18 nm. The obtained CZTSe nanoparticles were used to fabricate a light absorber layer in the CZTSe solar cells. The cell exhibited performance, with short-circuit current density of ~ 30.8 mA/cm2, open-circuit voltage of 0.39 V, ?ll factor of 0.47 and conversion ef?ciency of 5.8%.
关键词： Hot-injection method,Single phase,CZTSe nanoparticles,Copper-poor composition
更新于2025-09-23 15:19:57
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Phenanthrenea??Fuseda??Quinoxaline as Key Building Block for Highly Efficient and Stable Sensitizers in Copper Electrolyte Based Dyea??Sensitized Solar Cells
摘要： Dye-sensitized solar cells (DSSCs) based on Cu(II/I) bipyridyl or phenanthroline complexes as redox shuttles have achieved very high open-circuit voltages (VOC, > 1 V). However, their short-circuit photocurrent density (JSC) has remained modest. The challenge for increasing the JSC is expected to extend the spectral response of sensitizers to the red or NIR region while maintaining efficient electron injection in the mesoscopic TiO2 film and fast regeneration by the Cu(I) complex. Here, we report two new D-A-π-A featured sensitizers coded HY63 and HY64, which employ either benzothiadiazole (BT) or phenanthrene-fused-quinoxaline (PFQ) as the auxiliary electron-withdrawing acceptor moiety. In spite of very similar energy levels and absorption onsets, HY64-based DSSCs outperform largely their HY63 counterpart, achieving an outstanding power conversion efficiency (PCE) of 12.5% with superior stability. In depth studies of interfacial charge carrier dynamics show that PFQ is superior to BT in retarding charge recombination resulting in near quantitative collection of photogenerated charge carriers.
关键词： sensitizers,light-harvesting,dye-sensitized solar cells,copper redox shuttle,charge recombination
更新于2025-09-23 15:19:57
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Study of Thermal Effect in the Interaction of Nanosecond Capillary Discharge Extreme Ultraviolet Laser with Copper
摘要： Interaction of Extreme Ultraviolet (EUV) laser with matters is an attractive subject since novel phenomena always occur under the e?ect of high energy photons. In this paper, the thermal e?ect involved in the interaction of a capillary discharge 46.9 nm laser with copper was studied theoretically and experimentally. The temperature variation of the laser-irradiated region of copper was calculated. According to the results, the copper surface was ablated obviously and presented the trace of melting, evaporation, and resolidi?cation, which suggested the thermal e?ect occurred on the surface during the laser irradiation.
关键词： laser-induced damage,thermal e?ect,copper,46.9 nm laser
更新于2025-09-23 15:19:57
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Ionic Self-Assembled Luminescent Nanospheres from Cationic Polyelectrolyte and Eu-Containing Polyoxometalate
摘要： Using the ionic self-assembly (ISA) strategy to combine Eu-containing polyoxometalates (Eu-POMs) and organic molecules mainly through noncovalent electrostatic interactions can protect Eu-POMs from solvent quenching of luminescence and enhance their processability. For this reason, a cationic polyelectrolyte, branched polyethyleneimine (PEI), and a Eu-POM, Na9(EuW10O36)·32H2O (EuW10), were used here to construct luminescence-enhanced spherical aggregates with diameters ranging from 50 to 200 nm. At a fixed concentration of EuW10, the phase behavior and luminescence properties of the mixture could be modulated by the PEI concentration. Such ISA-induced aggregates could effectively shield water molecules and result in better photophysical properties. Compared to bare EuW10, the absolute quantum yield and lifetime of luminescence for aggregates increased 10 and 5 times, respectively. Meanwhile, the sensitivity of the EuW10 coordination structure to the environment made it possible for obtained aggregates being used to detect either copper cations or permanganate anions due to their strong specific quenching effects to luminescence. Such a new type of luminescent soft material not only provided a reference for exploring the luminescence enhancement mechanism of lanthanide through self-assembly in aqueous solution but also exhibited potential in detection by luminescence analysis.
关键词： polyoxometalates,permanganate detection,polyethyleneimine,ionic self-assembly,copper detection,luminescence enhancement,luminescent nanospheres
更新于2025-09-23 15:19:57
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High Responsivity and External Quantum Efficiency Photodetectors Based on Solution-Processed Ni-Doped CuO Films
摘要： Photodetectors based on p-type metal oxides are still a challenge for optoelectronic device applications. Many effects have been paid to improve the performance and expand the detection range. Here, high-quality Cu1-xNixO (x=0, 0.2, and 0.4) film photodetectors were prepared by a solution process. The crystal quality, morphology, and grain size of Cu1-xNixO films can be modulated by Ni doping. Among the photodetectors, the Cu0.8Ni0.2O photodetector shows the maximum photocurrent value (6×10-7 A) under 635 nm laser illumination. High responsivity (26.46 A/W) and external quantum efficiency (5176 %) are also achieved for Cu0.8Ni0.2O photodetector. This is because the Cu0.8Ni0.2O photosensitive layer exhibits high photoconductivity, low surface states, and high crystallization after 20% Ni doping. Compared to the other photodetectors, the Cu0.8Ni0.2O photodetector exhibits the optimal response in the near-infrared region, owing to the high absorption coefficient. These findings provide a route to fabricate high performance and wide detection range p-type metal oxide photodetectors.
关键词： Copper oxide,Ni doping,photodetector,responsivity,external quantum efficiency
更新于2025-09-23 15:19:57
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Novel boron doped p-type Cu2O thin film as hole selective contact in c-Si solar cell
摘要： P-type Cu2O thin film doped with trivalent cation Boron is demonstrated for the first time as an efficient hole selective layer for c-Si heterojunction solar cell. Cu2O and Cu2O:B films were deposited by rf- magnetron sputtering and the optical and electrical properties of the doped and undoped films were investigated. Boron doping enhanced the carrier concentration and the electrical conductivity of the Cu2O film. The band alignment of the Cu2O:B/Si heterojunction was investigated using XPS and UPS measurements. The Cu2O:B/Si interface has a valance band offset of 0.08 eV which facilitates hole transport and a conduction band offset of 1.35 eV which block the electrons. A thin SiOx tunnel oxide interlayer was also explored as the passivation layer. The initial trials of incorporating this Cu2O:B layer as hole transporting layer in a single heterojunction solar cell with the structure, ITO/Cu2O:B/n-Si/Ag, and cell area of 1 cm2 yielded an open-circuit voltage of 370 mV, short-circuit current density of 36.5 mA/cm2 and an efficiency of 5.4 %. This p-type material could find potential applications in various optoelectronic applications like organic solar cells, TFTs, and LEDs.
关键词： Silicon heterojunction,Photovoltaics,Carrier selective solar cells,Sputtering,Copper Oxide,Hole Selective layer
更新于2025-09-23 15:19:57
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Optimization of Measuring Parameters for Two-dimensional Elemental Mapping in Laser-induced Breakdown Optical Emission Spectrometry Using 1-kHz Q-switched Nd:YAG Laser
摘要： This paper described how the lateral resolution of an elemental mapping was estimated in laser-induced breakdown optical emission spectrometry (LIBS), when the focus point of a high-frequency Q-switched Nd:YAG laser was moved on a sample surface, along with measuring the emission signal from the resultant plasma. Several measuring parameters were optimized to improve the lateral resolution; namely, they were an averaged laser power of 1 mJ/pulse, a laser repetition frequency of 1 kHz, a scanning rate of the laser beam of 0.5 mm/s, and an atmospheric gas pressure of He 1 000 Pa. Using these optimal parameters, a lateral resolution was obtained to be ca. 20 μm in the one-dimensional direction of laser scan. Furthermore, two model samples, in which regularly-aligned copper circles were deposited on a nickel plate, were irradiated by a scanning laser beam to determine actual resolving abilities both in a line direction along travelling the laser and in a two-dimensional direction over a certain sample area. The sample having an interval of 85 μm between the copper circles could give an emission image which was appropriately resolved in the two-dimensional as well as the one-dimensional direction; however, in the other sample having the 25-μm interval, the two-dimensional resolution became degraded compared to the resolution of the line scan, probably because the ablation grooves, which were left on the sample surface, had a width of more than 100 μm and were overlapped with each other in the observed area.
关键词： lateral resolution,copper,scanning laser beam,laser-induced breakdown plasma spectrometry,laser ablation
更新于2025-09-23 15:19:57
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Densification of pure copper by selective laser melting process
摘要： Pure copper is utilized as a material for products with complicated shape and high thermal conductivity such as heat exchangers. However, it is difficult to fabricate pure copper parts with high density by the selective laser melting (SLM) process. One of the reasons is considered to be its high thermal conductivity by which the heat in the melt pool rapidly diffuses away. Additionally, the lower rate of energy absorption of fiber laser power for pure copper makes the size of melt pool smaller. In this research, the optimum fabrication condition of high-purity 99.9% copper fabricated by SLM process was investigated by evaluating the density and microstructure. As a result, it was found that the optimum condition of laser power and scan speed are 800~900W and 300 mm/s, respectively, and the optimum energy density is around 1000 J/mm3, which is much higher than that of other materials due to high reflectivity and high thermal conductivity of pure copper. And also, it was found that the hatch pitch is important factor to achieve the densification of the as-built specimen and the optimum hatch pitch was 0.01 mm. The high density parts were successfully fabricated by the optimum fabrication condition. The maximum density of the as-built specimen was 96.6 % and was much higher than that of the as-built part already reported.
关键词： Microstructure,Copper,Density,Process parameter,Additive manufacturing
更新于2025-09-23 15:19:57
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Laser hardening of copper-iron pseudoalloy
摘要： The purpose of the study is to improve the performance characteristics of powder pseudo-alloy materials using surface heat treatment. Such materials have unique properties, for example, self-lubrication under dry friction conditions, high thermal conductivity coefficient, and high electro-erosion resistance. The disadvantage of powder pseudo-alloys is their relatively low strength. The paper considers the method of surface hardening by high-energy treatment - laser radiation. The paper describes the method of experimental research, describes the method of obtaining powder material, its chemical composition, shows the equipment used. The results of studies of the microstructure and microhardness of the surface layer of steel-copper powder pseudo-alloy after laser heat treatment (LHT) of a continuous-wave fiber laser with a maximum power of 1 kW are given, LHT modes are indicated, the influence of LHT parameters on the characteristics of the hardened layer is evaluated. It is revealed that the partial melting region in which melting occurs in the volumes of the fusible component (copper) in the initial structure and contacting segments of steel matrix is formed in the material in addition to the total melting zone. Then the quenching zone from the solid state follows, in which the maximal hardness up to 1000 HV is attained for best samples in the volume of martensite, which is formed in perlite colonies of the initial steel–copper material.
关键词： Steel–copper pseudoalloy,Microhardness,Abrasive wear,Laser heat treatment,Powder metallurgy,Microstructure
更新于2025-09-23 15:19:57