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Influence of bath temperatures on physical and electrical properties of potentiostatically deposited Cu2O thin films for heterojunction solar cell applications
摘要： In the present work, the influence of bath temperatures on structural, morphological, vibrational, optical, electrical and photo response properties of the electrochemically deposited cuprous oxide (Cu2O) thin films on fluorine doped tin oxide substrate is extensively investigated with the help of X-ray diffraction (XRD), scanning electron microscopy (SEM), Micro Raman spectroscopy, photo luminescence (PL) spectroscopy, UV–visible spectroscopy, LCR measurement, Keithley 4200 semiconductor characterization system respectively. XRD patterns reveal that the deposited Cu2O films have cubic structure grown along the preferential (111) orientation and the film deposited at 40 °C shows better crystalline nature when compared at 55 and 70 °C. The micro structural properties of films such as crystallite size (D), dislocation density (δ), micro strain (ε) and stacking fault probability (α) were calculated and discussed in detail. SEM displays a well-defined three side pyramid shaped morphology for the film deposited at 40 °C. Micro Raman and PL spectra reveal the film deposited at 40 °C by being better crystalline at a higher acceptor concentration. UV–Visible study shows that the optical energy band gap increases from 2.05 to 2.17 eV with an increase in bath temperature from 40 to 70 °C. The frequency-temperature dependence of impedance analysis shows a higher electrical conductivity for a film deposited at 40 °C compared to other bath temperatures. I-V measurement illustrates a good photoconductivity response for Cu2O thin film deposited at 40 °C compared to films deposited at 55 and 70 °C.
关键词： Micro Raman spectroscopy,X-ray diffraction,Photoconductivity,Cuprous oxide,Pyramid shape
更新于2025-11-19 16:46:39
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Optimal synthesis of antimony-doped cuprous oxides for photoelectrochemical applications
摘要： We investigated the influence of Sb dopant concentration on the structural, electrical, and photoelectrochemical properties of the photocathode cuprous oxide (Cu2O) thin films. The photoabsorber p-type Cu2O films were prepared by electrodeposition in ionic electrolytes including copper sulfate and antimony sulfate at 333 K and pH=10. The small amount of Sb doping contributes to the fast Cu ion transport to the substrate and ion consumption; consequently, the p-type Cu2O with high crystalline quality can be reproducibly synthesized with high electrical stability. Among the various samples, the mole fraction of c(Sb)/[c(Cu)+c(Sb)] = 0.75 mol % exhibits the best electrical resistivity and improved transparency in the infrared region, which is involved with the fast overlap of the nuclei crystals under 5 nm from the high nuclei density. Additionally, the post-thermal annealed Sb-doped Cu2O sample reveals an enhanced photocurrent of ~0.65 mA/cm2 vs. RHE (reversible hydrogen electrode) without metal catalysts.
关键词： Preferred orientation,Post annealing,Antimony doping,Photoelectrochemical cell,Cuprous oxide
更新于2025-09-23 15:23:52
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Facet-Dependent Photocatalytic Behaviors of ZnS-Decorated Cu <sub/>2</sub> O Polyhedra Arising from Tunable Interfacial Band Alignment
摘要： ZnS particles were grown over Cu2O cubes, octahedra, and rhombic dodecahedra for examination of their facet-dependent photocatalytic behaviors. After ZnS growth, Cu2O cubes stay photocatalytically inactive. ZnS-decorated Cu2O octahedra show enhanced photocatalytic activity resulting from better charge carrier separation upon photoexcitation. Surprisingly, Cu2O rhombic dodecahedra give greatly suppressed photocatalytic activity after ZnS deposition. Electron paramagnetic resonance (EPR) spectra agree with these experimental observations. Time-resolved photoluminescence (TRPL) profiles provide charge transfer insights. The decrease in the photocatalytic activity is attributed to an unfavorable band alignment caused by significant band bending within the Cu2O (110)/ZnS (200) plane interface. A modified Cu2O–ZnS band diagram is presented. Density functional theory (DFT) calculations generating plane-specific band energy diagrams of Cu2O and ZnS match well with the experimental results, showing charge transfer across the Cu2O (110)/ZnS (200) plane interface would not happen. This example further illustrates that the actual photocatalysis outcome for semiconductor heterojunctions cannot be assumed because interfacial charge transfer is strongly facet-dependent.
关键词： interfacial charge transfer,zinc sulfide,cuprous oxide,facet-dependent properties,heterojunctions,band alignment
更新于2025-09-23 15:23:52
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Sustainable Recovery of CO2 by Using Visible-Light-Responsive Crystal Cuprous Oxide/Reduced Graphene Oxide
摘要： A simple solution-chemistry method has been investigated to prepare crystal cuprous oxide (Cu2O) incorporated with reduced graphene oxide (designated as Cu2O-rGO-x, where x represents the contents of rGO = 1%, 5% and 10%) in this work. These Cu2O-rGO-x composites combine the prospective advantages of rhombic dodecahedra Cu2O together with rGO nanosheets which have been studied as visible-light-sensitive catalysts for the photocatalytic production of methanol from CO2. Among the Cu2O-rGO-x photocatalysts, the methanol yield photocatalyzed by Cu2O-rGO-5% can be observed to be 355.26 μmol g?1cat, which is ca. 36 times higher than that of pristine Cu2O nanocrystal in the 20th hour under visible light irradiation. The improved activity may be attributed to the enhanced absorption ability of visible light, the superior separation of electron–hole pairs, well-dispersed Cu2O nanocrystals and the increased photostability of Cu2O, which are evidenced by employing UV-vis diffuse reflection spectroscopy, photoluminescence, scanning electron microscopy/transmission electron microscopy and X-ray photoelectron spectroscopy, respectively. This work demonstrates an easy and cost-effective route to prepare non-noble photocatalysts for efficient CO2 recovery in artificial photosynthesis.
关键词： cuprous oxide,solar energy,visible-light-driven,graphene,CO2 conversion
更新于2025-09-23 15:22:29
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Biomimetic Polyimide-Supported Cuprous Oxide Photocatalytic Film with Tunable Hydrophobicity, Improved Thermal Stability, and Photocatalytic Activity toward CO <sub/>2</sub> Reduction
摘要： Flexible and thermally stable polyimide (PI) ?lms containing a hierarchical surface structure were synthesized as substrates to support visible-light active cuprous oxide for photocatalytic reduction of carbon dioxide for the ?rst time. With the nanocasting technique, the surface structure on the leaves of Xanthosoma sagittifolium was successfully duplicated on PI ?lms. Followed by the ion-exchange process and adequate thermal treatment, cuprous oxide nanoparticles were successfully immobilized on the arti?cial PI leaves and exhibited the capability to photoreduce carbon dioxide into carbon monoxide under visible-light illumination. With the selection of biomimetic structures and adjustment of fabrication parameters, the hydrophobicity and optical absorption edge of the photocatalytic ?lm were tunable. An increase in hydrophobicity improved the yield of carbon monoxide. The introduction of a hierarchical structure on the surface and cuprous oxide within the matrix dramatically enhanced the thermal stability of the PI ?lm. The ?exible photocatalytic ?lm is a promising material for the applications requiring high mechanical and thermal stability, such as industrial ?ue-gas treatments.
关键词： Thermal Stability,CO2 Reduction,Hydrophobicity,Polyimide,Photocatalytic,Biomimetic,Cuprous Oxide
更新于2025-09-23 15:22:29
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Interaction of Rydberg excitons in cuprous oxide with phonons and photons: optical linewidth and polariton effect
摘要： We demonstrate that the optical linewidth of Rydberg excitons in Cu2O can be completely explained by scattering with acoustical and optical phonons, whereby the dominant contributions stems from the non-polar optical 3G- and 5G- modes. The consequences for the observation of polariton effects are discussed. We find that an anti-crossing of photon and exciton dispersions exists only for states with main quantum numbers n > 28, so polariton effects do not play any role in the experiments reported up to now.
关键词： polaritons,phonon scattering,Rydberg excitons,cuprous oxide
更新于2025-09-23 15:21:01
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A review on sustainable routes of synthesis and applications of Cuprous Oxide Nanoparticles and their Nanocomposites.
摘要： Nature acts like a “Bio-Laboratory” consisting of plants, algae, fungi, yeast etc. which are composed of bio-molecules. These naturally occurring bio-molecules play a vital role in the synthesis of Cuprous oxide (Cu2O) nanoparticles (NPs) and their nanocomposites (NCs) with distinct shapes and sizes, thereby acting as a driving force for designing safer, greener and sustainable routes using less hazardous chemicals. The present review focuses on the eco-friendly protocols for synthesis of Cu2O NPs and their NCs, characterisation techniques and various applications in organic catalysis, biosensing, environmental remediation and medicinal chemistry. The pivotal role of Cu2O NPs and their NCs in catalysing coupling reactions (C-C and C-N), multicomponent, oxidation-reduction and heterocyclic reactions have been higlighted. It emphasises its role in sustainability of the environment and its range of versatility in heterogenous catalysis. Furthermore, their use in biosensing (electrochemical detection) generates special interest in bioscience and clinical diagnosis. Their significance ensures to build a bridge between academic research and safety of the surroundings.
关键词： green chemistry,medicinal applications,biogenic synthesis,environmental remediation,biosensing,catalysis,Cuprous oxide nanoparticles
更新于2025-09-19 17:15:36
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Facet-Dependent Optical Properties of Semiconductor Nanocrystals
摘要： Recent observations of facet-dependent electrical conductivity and photocatalytic activity of various semiconductor crystals are presented. Then, the discovery of facet-dependent surface plasmon resonance absorption of metal–Cu2O core–shell nanocrystals with tunable sizes and shapes is discussed. The Cu2O shells also exhibit a facet-specific optical absorption feature. The facet-dependent electrical conductivity, photocatalytic activity, and optical properties are related phenomena, resulting from the presence of an ultrathin surface layer with different band structures and thus varying degrees of band bending for the {100}, {110}, and {111} faces of Cu2O to absorb light of somewhat different wavelengths. Recently, it is shown that the light absorption and photoluminescence properties of pure Cu2O cubes, octahedra, and rhombic dodecahedra also display size and facet effects because of their tunable band gaps. A modified band diagram of Cu2O can be constructed to incorporate these optical effects. Literature also provides examples of facet-dependent optical behaviors of semiconductor nanostructures, indicating that optical properties of nanoscale semiconductor materials are intrinsically facet-dependent. Some applications of semiconductor optical size and facet effects are considered.
关键词： surface band bending,semiconductors,facet-dependent properties,cuprous oxide,nanocrystals
更新于2025-09-19 17:15:36
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Elucidating the origin of external quantum efficiency losses in cuprous oxide solar cells through defect analysis
摘要： Heterojunction Cu2O solar cells are an important class of Earth-abundant photovoltaics that can be synthesized by a variety of techniques, including electrochemical deposition (ECD) and thermal oxidation (TO). The latter gives the most efficient solar cells of up to 8.1% reported in the literature, but is limited by low external quantum efficiencies (EQE) in the long wavelength range (490–600 nm). By contrast, ECD Cu2O gives higher short wavelength EQEs of up to 90%. We elucidate the cause of this difference by characterizing and comparing ECD and TO films using impedance spectroscopy and fitting with a lumped circuit model to determine the trap density, followed by simulations. The data indicates that TO Cu2O has a higher density of interface defects, located approximately 0.5 eV above the valence band maximum (NV), and lower bulk defect density thus explaining the lower short wavelength EQEs and higher long wavelength EQEs. This work shows that a route to further efficiency increases of TO Cu2O is to reduce the density of interface defect states.
关键词： Atmospheric pressure spatial atomic layer deposition,chemical vapour deposition,Interface and bulk defects,Impedance spectroscopy,Cuprous oxide solar cells,Quantum efficiency
更新于2025-09-19 17:13:59
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Cu 2 O Layer Analysis and Optimization Based on a Metal-Oxide Tandem Heterojunction Solar Cell
摘要： An analysis of Cu2O layer has been conducted for advanced thin film solar cells based on a tandem heterojunction design with metal oxides, in order to evaluate and improve the metal-oxide subcell performance. We have considered a promising cell design with metal oxide active and passive layers. We have used a comparative analysis based on numerical modeling in wxAMPS for device characteristics, with respect to the layer’s thickness and doping. It has been proved that the metal oxides hold great potential of optimization and have a big impact for the improvement of this design. The assessment has been made for the Cu2O/ZnO segment cell, as a basis, with the position of the defects in the middle of the band gap. The simulation methodology could be used for design and material performance optimization. The calculated values were compared with the experimental ones reported in the literature.
关键词： metal-oxide,heterojunction solar cell,cuprous oxide layer
更新于2025-09-16 10:30:52