CuO2 Layers Research Articles

First-Principles Prediction of Structural Distortions in the Cuprates and Their Impact on the Electronic Structure

Materials-realistic microscopic theoretical descriptions of copper-based superconductors are challenging due to their complex crystal structures combined with strong electron interactions. Here, we demonstrate how density functional theory can accurately describe key structural, electronic, and magnetic properties of the normal state of the prototypical cuprate Bi2Sr2CaCu2O8+x (Bi-2212). We emphasize the importance of accounting for energy-lowering structural distortions, which then allows us to (a) accurately describe the insulating antiferromagnetic (AFM) ground state of the undoped parent compound (in contrast to the metallic state predicted by previous studies); (b) identify numerous low-energy competing spin and charge stripe orders in the hole-overdoped material nearly degenerate in energy with the AFM ordered state, indicating strong spin fluctuations; (c) predict the lowest-energy hole-doped crystal structure including its long-range structural distortions and oxygen dopant positions that match high-resolution scanning transmission electron microscopy measurements; and (d) describe electronic bands near the Fermi energy with flat antinodal dispersions and Fermi surfaces that are in agreement with angle-resolved photoemission spectroscopy (ARPES) measurements and provide a clear explanation for the structural origins of the so-called “shadow bands.” We also show how one must go beyond band theory and include fully dynamic spin fluctuations via a many-body approach when aiming to make quantitative predictions to measure the ARPES spectra in the overdoped material. Finally, regarding spatial inhomogeneity, we show that the local structure at the CuO2 layer, rather than dopant electrostatic effects, modulates the local charge-transfer gaps, local correlation strengths, and by extension the local superconducting gaps. Published by the American Physical Society 2024

Parameter influences of FTO/ZnO/Cu₂O photodetectors fabricated by electrodeposition and spray pyrolysis techniques

This study investigates fabrication of transparent conductive glass using fluorine-doped tin oxide (FTO) as a more affordable alternative to indium tin oxide (ITO) in photovoltaic applications. To enhance conductivity, a ZnO layer was deposited on FTO, followed by a Cu2O layer via electrodeposition. The synthesis parameters are varied to determine their effect on the reaction and to identify the optimal conditions. The characteristic of FTO/ZnO/Cu2O studied using XRD, SEM annexed with EDX, IV testing and visible light absorption spectroscopy to disclose its optoelectronic applications. The FTO layers were produced via spray pyrolysis, with optimal deposition achieved at 400 °C and efficiency value 0.0149 %, resulting in a dense, transparent structure. Meanwhile the efficiency of samples at temperatures of 350°C, 450°C, and 500°C are 0.0032 %, 0.0042 %, and 0.0037 %. From the efficiency results, the optimal thickness of the Cu2O layer was obtained at a duration of 30 min, which was 0.0380 %, while the other durations of 1 hour, 2 h, and 3 h were 0.0149 %, 0.0076 %, and 0.0056 %. The best efficiency was obtained at an optimum pH of 10 with a value of 0.0038 %, promoting crystal growth along the (111) plane. While at pH variations of 8, 9, 11, and 12, the efficiency values were 0.0016 %, 0.0083 %, 0.0083 %, and 0.0073 %, respectively. I-V testing of FTO/ZnO:Mg/ Cu2O with varying electrodeposition voltage show that the efficiency of samples at voltage 5 V, 10 V, 15 V, 20 V, and 0.0128, 0.0093, 0.0036, 0.0053 and 0.0383 %. The optimum conditions for fabricated the samples was achieved with a 30-minute electrodeposition duration at 25 V and pH 10, as confirmed through I-V testing. The study highlights the influence of pyrolysis temperature, electrodeposition time, and pH on the optical and electrical properties of the glass, with optimized conditions yielding improved photoresponse performance.

A Sandwich-structured EVA/Cu2O/Cu Composite Current Collector to Suppress the Lithium Dendrite Growth.

The proliferation of lithium dendrites has long posed a formidable hurdle in the widespread adoption of lithium metal batteries, thereby necessitating the urgent resolution of how to effectively mitigate their growth as the paramount challenge in the realm of energy storage. Herein, we havecrafted a novel sandwich-structured current collector comprising an ethylene-vinyl acetate polymer (EVA)/Cu2O/Cu configuration, where the EVA thin film acts as a protective barrier, passivating the lithium metal anode, while the Cu2O layer fosters lithiophilic sites conducive to uniform lithium nucleation. Our experiments reveal that the EVA thin film adeptly prevents direct contact and subsequent reactions between the lithium metal and the electrolyte, enhancing the ion mobility of Li+ ions, ultimately leading to a even distribution of lithium deposition. In a Li-Cu half-cell, the incorporation of the EVA film increases the nucleation potentials but dramatically reduces polarization potentials after 50 cycles of charge-discharge processes. Remarkably, the Li-Cu half-cells equipped with EVA-coated current collectors exhibit lower electrochemical resistances, translating into significantly extended cycle lives. This work indicates the sandwich architecture (thin film/lithium metal/lithiophilic compounds) is a promising contender for achieving long-lasting, stable lithium anodes.

Wavelength dependence of linear birefringence and linear dichroism of Bi2−xPbxSr2CaCu2O8+δ single crystals

Copper oxide high-temperature superconductors, such as Bi2Sr2CaCu2O8+δ (Bi2212), have garnered extensive research interest due to their high critical temperatures (Tc) surpassing the Bardeen–Cooper–Schrieffer (BCS) limit. The two-dimensional CuO₂ plane is widely regarded as the most crucial element of high-Tc cuprate superconductors. The anisotropy of this CuO₂ layer remains a topic of ongoing interest. Although a few experimental results have reported strong optical anisotropy in both ab and ac-planes of Bi2212 through optical “reflectivity” measurements, there is a lack of studies focusing on the optical anisotropy of these materials using optical “transmittance” measurements by utilizing ultraviolet and visible light. Using a generalized high-accuracy universal polarimeter, we observed significant linear birefringence and linear dichroism peaks in the UV region at room temperature. To investigate the origin of the significant optical anisotropy, single crystals of Bi2−xPbxSr2CaCu2O8+δ with different lead contents (x = 0, 0.4, and 0.6) were grown using the floating zone method, and the wavelength dependencies of linear birefringence and linear dichroism along the c axis were measured. The insights gained into the optical anisotropy of Bi2−xPbxSr2CaCu2O8+δ from this study are significant for discussing its origin of the mechanism of high-Tc superconductivity.

Synthesis and Characterization of ZnO/Cu<sub>2</sub>O and Co co-doped Ag-ZnO/Cu<sub>2</sub>O Nanoparticles with Possible Photovoltaic Applications

The Photovoltaics phenomenon is one of the major turning points in the battle against the depletion of fossil fuels. Sunlight is the main resource in photovoltaics, but there remains a quest to harvest it efficiently to generate electricity. This study is focused on designing basic, cost-effective prototype solar cells using ZnO/Cu2O nanoparticles (NPs) and Co(cobalt) co-doped Ag-ZnO/Cu2O NPs under normal university laboratory conditions. ITO-coated glass was used as the substrate of the solar cell and a modified low-temperature chemical bath deposition method was used for fabrication. Both ZnO and Cu2O NPs were synthesized by aqueous precipitation methods and the fabrication was performed successfully using ZnO and Cu2O NPs. However, the fabrication with Co co-doped Ag-ZnO and Cu2O NPs requires more research since the Co co-doped Ag-ZnO NPs were synthesized by solvothermal method, and it appeared as a fine powder which was not thick enough to hold onto the Cu2O layer. The UV-spectroscopic analysis confirmed the characteristic band of ZnO NPs at 367.5 nm, Cu2O NPs at 360 nm, and Co co-doped Ag-ZnO NPs at 378 nm. The FTIR spectrum showed sharp peaks at 460 cm-1 and 606 cm-1 for the corresponding Zn-O bond and Cu-O bond, respectively with a broad peak at 1329 cm-1 for Cu2O FTIR, due to the chemisorbed and/or physiosorbed H2O and CO2 molecules on the surface of the nanostructure. The EDX analysis showed the presence of slight carbon impurity in ZnO NPs which resulted in a deviated XRD pattern while Cu2O NPs showed the characteristic XRD pattern. The solar cell illuminated under three different lux conditions, had the characteristic J-V plot when measured through Gamry Potentiostat.

Semitransparent Cu2O Films Based on CuO Back Layer for Photoelectrochemical Water Splitting and Photovoltaic Applications.

Cuprous oxide (Cu2O) as an intrinsic p-type semiconductor is promising for solar energy conversion. The major challenge in fabricating Cu2O lies in achieving both high transparency and high performance in a tandem device. The Cu2O photocathodes often employ gold as the back contact layer. However, it is not an optimal choice in tandem device due to its poor transmission, scarcity, and electron-hole recombination at the interface of Au and Cu2O. Here, we presented a facile method that utilizes the earth-abundant material copper oxide (CuO) to fabricate highly transparent Cu2O devices. The maximum transmittance of the Cu2O film on CuO (FTO/CuO/Cu2O) increased from 42 % to 58 % compared with Cu2O film on Au (FTO/Au (3 nm)/Cu2O) in 550-800 nm. After coating atomic layer deposition (ALD) layers and hydrogen evolution reaction (HER) catalyst, the photocurrent density at 0 V (versus RHE) of the semitransparent Cu2O photocathode with CuO as the back layer for photoelectrochemical (PEC) water splitting reached -4.9 mA cm-2, which showed a 24.5 % improvement compared with FTO/Au/Cu2O photocathode. Moreover, expanding the CuO layer strategy to the field of solar cells enables Cu2O solar cells to achieve a PCE of 2.37 %.

Enhancing solar cell efficiency: In-situ polymerization with Cu2O@CuO core-shell nanostars

Herein, Cu2O@CuO core-shell nanostars were prepared via a solution-processed method. High-resolution transmission electron microscopy and X-ray diffraction analyses confirmed that the Cu2O nanostars were consistently enclosed by a CuO layer. Dibromo (DB)-3,4-ethylenedioxythiphene (EDOT) monomer was prepared from commercially available 3,4-ethylenedioxythiphene via a common bromination method. The Cu2O@CuO core-shell nanostars were blended with the DBEDOT monomer and heated to 70 °C to form a nano-hybrid hole transport material (HTM) for application in solid-state dye-sensitized solar cells (ssDSCs). The nanohybrid is systematically characterized through scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform spectroscopy. The photovoltaic performance of the ssDSCs was optimized by varying the Cu2O@CuO core-shell nanostars concentration in the nanohybrid HTM from 1 to 3 wt%, while maintaining the concentration of the DBEDOT monomer at 1wt%. In addition, the electrochemical properties of the nanohybrid HTM were explored through electrochemical impedance spectrometry measurements. Among the analyzed samples, the 1 wt% Cu2O@CuO core-shell nanostars in the nanohybrid HTM show the best efficiency. This method establishes the possibility of applying high-performance organic/inorganic-based nanohybrid HTMs in ssDSCs.

Investigating the effect of Cu underlayer and FTO etching towards photoelectrochemical performance enhancement of Cu2O photoelectrode

Cuprous oxide (Cu2O) exhibits potential as a photoactive material for photoelectrochemical water splitting, owing to its appropriate bandgap, efficient charge carrier separation, and ability to enhance solar-driven hydrogen production. This study investigates the influence of substrate etching, Cu underlayer and Cu2O electrodeposition time, and annealing time on enhancing the photoelectrochemical (PEC) performance. Electrodeposition and thermal oxidation techniques were used to fabricate the Cu2O/Cu/FTOe-A photocathode. It has been observed that FTO etching improves adhesion, light transmission, and efficiency. A Cu underlayer also impacts the PEC performance, wherein an ideal thickness of Cu leads to enhanced PEC performance. This study also focuses on the annealing time that leads to CuO layers and nanowires forming on the Cu2O surface. The structural and chemical changes before and after annealing are confirmed via XRD, XPS, AFM and FESEM analyses. UV–Vis analysis also reveals that the presence of Cu underlayer, FTO etching, and the annealing process affect the electrical properties and light absorption capacities of the Cu2O photoelectrode. Electrochemical impedance analysis (EIS) and Mott-Schottky analysis have provided insights into the enhanced charge transfer properties and band bending in the Cu2O/Cu/FTOe-A, resulting in enhanced PEC performance. Overall, this study provides significant insights into the understanding and enhancement of Cu2O/Cu/FTOe-A photocathodes for potential use in PEC water splitting applications.

Intrinsic Josephson junction characteristics of Nd2-xCexCuO4 /SrTiO3 epitaxial films

The current-voltage (I-V) properties along the c axis on Nd2-xCexCuO4/SrTiO3 epitaxial films with x = 0.145, 0.15 were investigated. For all the samples it has been established that the I-V characteristics exhibit several resistive branches, which correspond to the resistive states of individual Josephson junctions. The results confirm the idea of a tunneling mechanism between the CuO2 layers (superconductor - insulator - superconductor junction) for the investigated Nd2-xCexCuO4 compound. The I-V dependence of this compound with x = 0.15 points out on the nonmonotonic nature of the d-wave or anisotropic s-wave symmetry order parameter associated with the coexistence of superconductivity and antiferromagnetic fluctuations.

Hydrogen activation by rhodium under the cover of a copper oxide thin film

The activation of reactants by catalytically active metal sites at metal-oxide interfaces is important for understanding the effect of metal-support interactions on nanoparticle catalysts and for tuning activity and selectivity. Using a combined experimental and theoretical approach, we studied the activation of H2 and the effect of CO poisoning on isolated Rh atoms completely or partially covered by a copper oxide (Cu2O) thin film. Temperature-programmed desorption (TPD) experiments conducted in ultra-high vacuum (UHV) show that neither a partially nor a fully oxidized Cu2O layer grown on a Rh/Cu(111) single-atom alloy can activate hydrogen in UHV. However, in situ ambient pressure X-ray photoelectron spectroscopy (AP-XPS) experiments performed at elevated H2 pressures reveal that Rh significantly accelerates the reduction of these Cu2O thin films by hydrogen. Remarkably, the fastest reduction rate is observed for the fully oxidized sample with all Rh sites covered by Cu2O. Both TPD and AP-XPS data demonstrate that these covered Rh sites are inaccessible to CO, indicating that Rh under Cu2O is active for H2 dissociation but cannot be poisoned by CO. In contrast, an incomplete oxide film leaves some of the Rh sites exposed and accessible to CO, and hence prone to CO poisoning. Density functional theory calculations demonstrate that unlike many reactions in which hydrogen activation is rate limiting, the rate-determining step in the dissociation of H2 on thin-film Cu2O with Rh underneath is the adsorption of H2 on the buried Rh site, and once adsorbed, the dissociation of H2 is barrierless. These calculations also explain why H2 can only be activated at higher pressures. Together, these results highlight how different the reactivity of atomically dispersed Rh in Cu can be depending on its accessibility through the oxide layer, providing a way to engineer Rh sites that are active for hydrogen activation but resilient to CO poisoning.

Decoupled High-Mobility Graphene on Cu(111)/Sapphire via Chemical Vapor Deposition.

The growth of high-quality graphene on flat and rigid templates, such as metal thin films on insulating wafers, is regarded as a key enabler for technologies based on 2D materials. In this work, the growth of decoupled graphene is introduced via non-reducing low-pressure chemical vapor deposition (LPCVD) on crystalline Cu(111) films deposited on sapphire. The resulting film is atomically flat, with no detectable cracks or ripples, and lies atop of a thin Cu2O layer, as confirmed by microscopy, diffraction, and spectroscopy analyses. Post-growth treatment of the partially decoupled graphene enables full and uniform oxidation of the interface, greatly simplifying subsequent transfer processes, particularly dry-pick up - a task that proves challenging when dealing with graphene directly synthesized on metallic Cu(111). Electrical transport measurements reveal high carrier mobility at room temperature, exceeding 104cm2V-1s-1 on SiO2/Si and 105cm2V-1s-1 upon encapsulation in hexagonal boron nitride (hBN). The demonstrated growth approach yields exceptional material quality, in line with micro-mechanically exfoliated graphene flakes, and thus paves the way toward large-scale production of pristine graphene suitable for high-performance next-generation applications.

Enhancing Photoelectric Response of Self-powered UV and Visible Detectors Using CuO/ZnO NRs Heterojunctions.

Understanding the development and performance of UV photodetectors is crucial, given their extensive applications in both military and civilian sectors. The evolution of self-powered photodetectors, especially those based on heterojunction nanostructures, has demonstrated significant potential for enhancing both device efficiency and functionality. By exploring the effects of material composition and structural design, can optimize these devices for improved photoelectric response and energy efficiency. In this study, we prepared the CuO/ZnO NRs heterojunction photodetector on an ITO substrate to enhance photoelectric response of UV detectors. The fabrication process utilized the hydrothermal method and the spin coating technique. The effect of CuO concentration on the optical response of the photodetector under UV radiation at wavelengths of 405nm and 385nm was investigated. The samples were characterized using FESSEM, XRD, EDX, and UV-Vis spectra. The device is further distinguished by its standard I-V curves and photocurrent-time curves, which demonstrate the device's behavior under various light conditions. The prepared thin films are polycrystalline, with CuO layers displaying monoclinic phases and ZnO layers exhibiting a hexagonal wurtzite phase. All samples have the potential to exhibit photovoltaic properties and self-powered capabilities. Furthermore, the I-V curve confirms that the photocurrent mechanism of these junctions adheres to the recombination standard, in addition to demonstrating correction behavior. A sample with a CuO concentration of 0.1M shows the highest photosensitivity, reaching 340,700%, and a photocurrent gain (Iph/Idark) of 3,408 when exposed to light irradiation at 405nm. Additionally, it exhibits a rapid response time of 0.8s.

Improved interfacial mechanical properties between PZT piezoelectric ceramic and Ag metallization layer by in-situ-formed CuO nanoparticles

In-situ-formed CuO nanoparticles were used to improve the interfacial mechanical properties between lead zirconate titanate (PZT) ceramic and metallization layer. The effects of CuO particles on the mechanical properties of PZT/Ag interfaces were studied, and the damage evolutions of the PZT-CuO/Ag interfaces were analyzed. The results showed that both the maximum peeling stress σmax and shear stress τmax of the PZT-CuO/Ag interfaces increased by approximately 200 %, while the critical fracture energy GIC of the interface was increased at most by seven times. The enhanced mechanical properties of the PZT-CuO/Ag interfaces originated from the high bonding strength between CuO and Ag layer and the effective stress concentration relief. Crack deflection and crack pinning effects promoted the enhancement of interfacial fracture toughness. The optimal size of the CuO particles at the PZT/Ag interface was approximately 100 nm. Notably, the electron transport between the PZT ceramic and Ag layer was not degraded with the introduction of CuO nanoparticles.

Electrochemical Corrosion Behavior and the Related Mechanism of Ti3SiC2/Cu Composites in a Strong Acid Environment.

The electrochemical corrosion behaviors of Ti3SiC2/Cu composites in harsh media including dilute HNO3 and concentrated H2SO4 were studied in detail and the related corrosion mechanisms were explored. Under open-circuit potential, the corrosion resistance of Ti3SiC2/Cu in dilute HNO3 was worse than that in concentrated H2SO4. In dilute HNO3, Ti3SiC2/Cu exhibited a typical passivation character with a narrow passivation interval. During the corrosion process, the dissolution of Cu-Si compounds resulted in the destruction of the passivation layer on the surface. Additionally, with the increasing of the potentials, the oxidation of Cu and Si atoms led to the generation of the oxide film again on the surface. In concentrated H2SO4, the Ti3SiC2/Cu composite was covered by a double-layered passivation layer, which was composed of an internal layer of TiO2 and an external layer of Cu2O and SiO2. This was because Cu diffused into the surface and was oxidized into Cu2O, which formed a denser oxidized film with SiO2. In addition, it was found that Ti3SiC2/Cu has better corrosion resistance in concentrated H2SO4.

Effect of thiol adsorption on the electrical resistance of copper ultrathin films

The impact of thiol adsorption on thin copper films, covered with a copper oxide layer, was investigated using electrical resistance measurements at various stages: during film growth, aging, exposure to air, and immersion in thiol solutions. Thin copper films (20 nm) were thermally evaporated, with variations in substrate temperature (RT, 330 and 390 K). Films deposited at 330 K exhibited the smallest percolation thickness and aging rates due to their compact morphology, showcasing lower surface roughness and correlation length. Exposure to air led to the formation of a Cu2O layer on the film surface. Subsequent immersion in a dodecanethiol solution in ethanol resulted in a resistance increase, ranging from 0.1 % to 0.4 %. This change was dependent on the substrate temperature, with the largest difference observed at 330 K. This observation suggests that samples grown at this temperature exhibited the highest electron-surface scattering. Moreover, by depositing a chromium surfactant layer, the impact of this scattering mechanism was amplified, leading to a resistance increase of up to 1.2 %. Mayadas-Shatzkes theory provided a good description of these resistance changes. The negatively charged S-head of the adsorbed thiols alters the electric field experienced by conduction electrons in the Cu2O/Cu interface, modifying the electron-surface scattering.

Corrosive behavior of copper canisters under air and aerobic groundwater at early stages of deep geological disposal

Copper oxidation at low temperatures below 140 °C and its effects on corrosive behavior in aerobic groundwater are investigated to estimate the intactness of canisters at early stages of disposal. The Cu coupon surface is covered by fine particles that form thin oxide layers after 30 d of oxidation; a thin Cu2O layer of thickness <100 nm is formed after oxidation at 40 °C; after oxidation at 140 °C, the Cu2O surface changes to a CuO layer of thickness <500 nm. The thickness of the Cu surface oxidized at 90 °C is between those of the surfaces oxidized at 40 and 140 °C. All Cu coupons exhibit similar current densities ranging from 0.77 to 1.87 μA cm−2, although the corrosion potential of the Cu coupon layered with Cu2O is higher than that of the others. Long-term oxidation tests for 406 d reveal no significant changes in the Cu surface at temperatures below 90 °C, indicating no significant change in the electrochemical behavior. The results of this study suggest that the storage of canisters at temperatures below 90 °C has no significant effect on the degradation of canister performance in long-term disposal.

Room-temperature electrodeposition of Cu2O layers and its low-temperature annealing for photoelectrochemical water splitting applications

Cuprous oxide layers were obtained on a conductive glass substrate via room-temperature electrochemical deposition from the electrolyte containing 0.4 M CuSO4, 3 M lactic acid (pH = 12) at −0.5 V vs. SCE for various durations (from 0.25 to 3 h). Physicochemical properties of as-received FTO/Cu2O materials were characterized using SEM, PXRD, and UV–Vis DRS. The photoelectrochemical (PEC) properties of the obtained electrodes were evaluated in detail by analyzing the influence of the energy of monochromatic radiation, and the applied polarization on the resulting photocurrent transients. It was found that Cu2O crystals are getting bigger and sharper with prolonged electrosynthesis duration and a slight decrease in the band gap energy from 2.4 to 2.1 eV with increasing deposition duration was observed. Moreover, this trend was also reflected in PEC properties of resulted material, higher photocurrents were generated by the material deposited for 3 h. More importantly, this PEC response was enhanced by low-temperature (100 °C, 200 °C) annealing. Thermal treatment at 100 °C led to a noticeable improvement in the photoactivity of the samples. Further increasing post-treatment temperature to 200 °C resulted in a further six-fold increase in photocurrents. Finally, the calculated values of accumulated and dissipated charges indicated significantly lower surface recombination after thermal treatment.

Refining metallic nano-copper by electron-rich black carbon for superior Fenton-like catalysis in water purification: The capacitive regulation of corrosive electron transfer

Transition metals are promising catalysts for environmental remediation. However, their low reactivity, poor stability and weak reusability largely limit practical applications. Herein, we report that the electron-rich dissolved black carbon (DBC) incorporated into the nanoscale zero-valent copper (nZVCu) can boost intrinsic reactivity, structural stability and cyclic reusability for superior peroxymonosulfate (PMS) activation and pollutant degradation. A series of refractory pollutants can be effectively removed on the DBC/nZVCu, in comparison with the nZVCu reference. Hydroxyl radical (‧OH) is identified as the dominant reactive oxygen species by electron spin resonance (ESR) and chemical quenching tests, mediated by the metastable Cu(III) as the key reactive intermediate. The electron-rich DBC protects nanoscale Cu from oxidative corrosion to slow down the surface formation of inert CuO layer, rendered by the thermodynamically and dynamically capacitive regulation of corrosive electron transfer from metallic core. By this refining way, the conducive DBC improves the neighboring utilization of reactive electron during metal corrosion, oxidant activation, radical generation and pollutant degradation in Fenton-like catalysis. Our findings suggest that the ubiquitous DBC can be an efficient chelating agent to refine transition metals by serving as the surface deactivator and electron mediator, and take new insights into their environmental and agricultural geochemistry.

Enhancing bonding strength between Cu and Cu2O through crystallographic orientation variation

Copper is a widely used material but is susceptible to oxidation under atmospheric conditions, resulting in the formation of oxide layers that are prone to cracking and peeling even under minimal mechanical stress. To address this issue, the development of a dense and solid copper oxide layer with strong oxide–copper interfacial bonding is crucial; however, achieving such strong bonding is challenging owing to the substantial lattice misfit of approximately 18 %. This study presents a novel approach to create an adhesive and robust Cu2O layer on copper through a simple and reproducible heat treatment procedure conducted under extremely low air pressures in vacuum conditions. Remarkably, an unexpected reduction in lattice misfit at the interface is achieved by promoting the growth of a large-grain oxide layer that fully covers the copper surface. Despite the presence of arbitrary crystallographic relationships between copper and Cu2O, the crystallographic orientation of copper is intentionally altered by introducing geometrically necessary dislocations and atomic array tilting, which results in the formation of a stable oxide layer that exhibits exceptional resistance against cracking, peeling, plastic deformation, and mechanical scratching. The effectiveness of this approach is demonstrated by the enhanced robustness and stability it imparts to copper oxides.

Novel dual absorber configuration for eco-friendly perovskite solar cells: design, numerical investigations and performance of ITO-C60-MASnI3-RbGeI3-Cu2O-Au

Perovskite solar cells (PSCs) are increasingly being used as the foundation of the worldwide photovoltaic (PV) industry because of their cost-effective production and durable stability. Perovskite materials, both organic and inorganic, possess distinct optical, mechanical, and electrical properties, such as a high absorption coefficient, a customizable band gap, and a synthesis method based on solutions. This study employed numerical investigations to devise and propose innovative solar cell configurations utilizing the SCAPS-1D simulator. This research presents a Perovskite solar cell design comprising an ITO-C60-MASnI3-RbGeI3-Cu2O-Au solar cell configuration. The unique arrangement of this setup incorporates the use of Indium Tin-oxide (ITO) as the upper contact layer, which is directly exposed to light. The electron transport layer (ETL) is composed of a 0.030 μm thick layer of C60, while the light-harvesting/absorber layers are made up of MASnI3 and RbGeI3, each with a thickness of 0.4 µm. A layer of Cu2O with a thickness of 0.12 μm is employed as the hole transport layer (HTL), whereas the back-contact layer consists of Au. A comparison research was conducted to examine the optimal device configuration. Comprehensive studies are performed to assess the effects of different variables on optimized device performance and power conversion efficiency (PCE). These factors include interface defect densities, thicknesses of different structural layers, band gaps, series and shunt resistance, and operational temperature. The current density (Jsc) is calculated as 32.7 mA/cm2 at an open circuit voltage (Voc) of 0.914 V. Additionally, we observed a power conservation efficiency (PCE) of 20.19 % and an improved fill factor (FF) value of 65.49 %. The ongoing investigations are likely to be valuable for the development and production of cost-effective and high-performance PSCs.