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TiO2/Cu2O heterojunctions for photovoltaic cells application produced by reactive magnetron sputtering
摘要： In this work, TiO2/Cu2O heterostructures were obtained in a two-step process with a direct current magnetron sputtering method. We studied the morphological properties and composition of the thin films by scanning electron microscopy. Optical properties and energy bands at the heterojunction were recorded using a spectrophotometer. Additionally, the current–voltage characteristics examined in both total darkness and with illumination were estimated to have an irradiation (radiation flux divided by area) of 1000 W/m2.
关键词： Titanium dioxide,Thin film,Solar cells,Cuprous oxide,Photovoltaic cells
更新于2025-09-16 10:30:52
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Valence-State Controllable Fabrication of Cu <sub/> 2– <i>x</i> </sub> O/Si Type-II Heterojunction for High-Performance Photodetectors
摘要： Cuprite, nominally cuprous oxide (Cu2O) but more correctly Cu2-xO, is widely used in optoelectronic applications due to its natural p-type, nontoxicity and abundant availability. However, the photoresponsivity of Cu2O/Si photodetectors (PDs) has been limited by the lack of high-quality Cu2-xO films. Herein, we report a facile room-temperature solution method to prepare high-quality Cu2-xO films with controllable x value which were used as hole selective transport layers in crystalline n-type silicon based heterojunction PDs. The detection performance of Cu2-xO/Si PDs exhibits a remarkable improvement via reducing the x value, resulting in the optimized PDs with high responsivity of 417 mA W-1 and fast response speed of 1.3 μs. Furthermore, the performance of the heterojunction PDs can be further improved by designing the pyramidal silicon structure, with enhanced responsivity of 600 mA W-1 and response speed of 600 ns. The superior photodetecting performance of Cu2-xO/n-Si heterojunctions is attributed to (i) the matched energy level band alignment, (ii) the low trap states in high-quality Cu2O thin films, (iii) the excellent light trapping. We expect the low-cost, highly efficient solution process would be of great convenience for large-scale fabrication of the Cu2-xO thin films and broaden the applications of Cu2-xO based optoelectronic devices.
关键词： photodetector,energy band alignment,Cuprous oxide,solution method,heterojunction
更新于2025-09-12 10:27:22
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Nitrogen-Doped Cu2O Thin Films for Photovoltaic Applications
摘要： Cuprous oxide (Cu2O) is a p-type semiconductor with high optical absorption and a direct bandgap of about 2.1 eV, making it an attractive material for photovoltaic applications. For a high-performance photovoltaic device, the formation of low-resistivity contacts on Cu2O thin films is a prerequisite, which can be achieved by, for instance, nitrogen doping of Cu2O in order to increase the carrier concentration. In this work, nitrogen-doped p-type Cu2O thin films were prepared on quartz substrates by magnetron sputter deposition. By adding N2 gas during the deposition process, a nitrogen concentration of up to 2.3 × 1021 atoms/cm3 in the Cu2O thin films was achieved, as determined from secondary ion mass spectroscopy measurements. The effect of nitrogen doping on the structural, optical, and electrical properties of the Cu2O thin films was investigated. X-ray diffraction measurements suggest a preservation of the Cu2O phase for the nitrogen doped thin films, whereas spectrophotometric measurements show that the optical properties were not significantly altered by incorporation of nitrogen into the Cu2O matrix. A significant conductivity enhancement was achieved for the nitrogen-doped Cu2O thin films, based on Hall effect measurements, i.e., the hole concentration was increased from 4 × 1015 to 3 × 1019 cm?3 and the resistivity was reduced from 190 to 1.9 ?·cm by adding nitrogen to the Cu2O thin films.
关键词： magnetron sputtering,thin film,nitrogen,cuprous oxide,doping
更新于2025-09-11 14:15:04
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Synergistic effects of CuO and Au nanodomains on Cu2O cubes for improving photocatalytic activity and stability
摘要： Cu2O is a promising photocatalyst, but it suffers from poor photocatalytic activity and stability, especially for Cu2O cubes. Herein, we report the deposition of CuO and Au nanodomains on Cu2O cubes to form dual surface heterostructures (HCs) to improve photocatalytic activity and stability. The apparent quantum efficiency of Au/CuO/Cu2O HCs was ca. 123 times that of pristine Cu2O. In addition, the Au/CuO/Cu2O HCs maintained nearly 80% of its original activity after eight cycles in contrast to five cycles for the Au/Cu2O material. Therefore, CuO and Au domains greatly improved the photocatalytic activity and stability of the Cu2O cubes due to the synergistic effect of the HCs.
关键词： Charge transfer,Sequential surface engineering,Photocatalytic activity,Stability,Cuprous oxide
更新于2025-09-11 14:15:04
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Selective reduction of nitrate to nitrogen gas by novel Cu2O-Cu0@Fe0 composite combined with HCOOH under UV radiation
摘要： The nitrate reduction by Fe-based materials has been extensively studied, however, the selectivity of nitrate reduction to nitrogen gas is very low, which hinders the application of this technology. In this study, a novel Cu2O-Cu0@Fe0 composite was synthesized and a strategy of Cu2O-Cu0@Fe0 composite combined with HCOOH under UV radiation as reducers for the nitrate reduction was established to improve the selective reduction of nitrate (NO3?) to nitrogen gas (N2). The Cu2O-Cu0@Fe0 composite was synthesized by simple chemical replacement and O2 oxidation process and characterized by SEM, EDS, XRD and XPS. The nitrate removal efficiency of 100% and the N2 selectivity of 95.4% were achieved in Cu2O-Cu0@Fe0/HCOOH/UV system when the initial nitrate concentration was 50 mg N/L and the reduction time was 60 min. The nitrate reduction efficiency was low by the role of alone or combinations of Cu2O-Cu0@Fe0 composite, HCOOH or UV radiation. The quick reduction of nitrate to nitrite was due to the synergistic effect of electrons from the galvanic-type cell consisting of Fe0 as anode and Cu0 as cathode, photoelectrons from Cu2O under UV radiation and CO2?? produced mainly via photochemical reaction between HCOOH and UV radiation. The subsequent conversion of nitrite to N2 was caused by CO2??, which was responsible for the high efficient reduction of nitrate to nitrogen gas in the Cu2O-Cu0@Fe0/HCOOH/UV system. Finally, the denitrification mechanism of the Cu2O-Cu0@Fe0/HCOOH/UV system was tentatively proposed.
关键词： Denitrification,Galvanic-type cell,Cuprous oxide,Nitrate reduction
更新于2025-09-10 09:29:36
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Study on the visible-light photocatalytic performance of Ag3PO4/Cu2O composite
摘要： Ag3PO4/Cu2O composites were prepared by a facile wet chemical method. The specimens were examined by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and UV–Vis diffuse reflectance spectroscopy. The specimens exhibited an excellent photocatalytic activity on the degradation of RhB than pure Ag3PO4 and Cu2O. Furthermore, the photocatalyst specimen was found to exhibit higher efficiency in hydrogen conversion. It was found that a 30? wt% Ag3PO4-loaded specimen showed an excellent hydrogen generation performance. The excellent photocatalytic activity was ascribed to the separation of e–h pairs via the Z-scheme method composed of Ag, Ag3PO4 and Cu2O. This study demonstrated the potential approach to the photocatalytic splitting water to release hydrogen as well as the environmental purification of organic pollutants under visible-light irradiation.
关键词： Cuprous oxide,Z-scheme,Photocatalysis,Water splitting
更新于2025-09-10 09:29:36
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Design of graphitic carbon nitride supported Ag–Cu2O composites with hierarchical structures for enhanced photocatalytic properties
摘要： A novel ternary photocatalytic nanocomposite, Ag–Cu2O/C3N4, has been successfully synthesized via a facile two-step reduction procedure at room temperature, wherein Ag nanoparticles are directly growing on the surface of Cu2O supported by C3N4 nanosheets. The resulting ternary Ag–Cu2O/C3N4 photocatalyst exhibits enhanced photocatalytic activity towards methyl orange (MO) degradation compared with its conterparts (Cu2O, spherical Ag–Cu2O and Cu2O/C3N4), demonstrating a removal rate of MO up to 95.7% within 30 min. The enhanced photocatalytic activity can be ascribed to the following factors: 1) the surface plasmon resonance effect of Ag nanoparticles broadening the visible light response of Cu2O; 2) the introduction of C3N4 functioning not only as a fast electron delivery but also a fine stabilizer to prevent the Ag–Cu2O composite from agglomeration. Mechanism studies reveal that MO is cracked into smaller fragments and the h+ is the main reactive species participating in the photocatalytic process. Moreover, the Ag–Cu2O/C3N4 photocatalyst also shows high photodegradation ability for another two representative azo dyes, acid orange II and congo red. This study demonstrates the potential of Ag–Cu2O/C3N4 in the degradation of azo dyes and also provides a guide to design of Cu2O-based ternary photocatalysts for further wastewater remediation.
关键词： Wastewater remediation,Cuprous oxide,Photocatalysis,C3N4 nanosheets,Fragments,Mechanism
更新于2025-09-09 09:28:46