Improvement of Photoelectrochemical and Stability Properties of Electrodeposited Cu2 O Thin Films by Annealing Processes (original) (raw)
Related papers
2023
This study examines the influence of electrolyte parameters on the synthesis of Cu2O semiconductor nanostructures. Cu2O nanostructures were synthesized using the electrodeposition method for application in photoelectrochemical water splitting. The study focused on investigating the effects of electrolyte pH and temperature during the synthesis process. Cuprous oxide is considered a promising p-type semiconductor due to its excellent light absorption in the solar spectrum window. It is an attractive semiconductor for photoelectrochemical water splitting, given its high theoretical efficiency for this process. Various characterizations including X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), and UV-Visible spectroscopy (UV-Vis) were used to analyze the structural properties of the synthesized Cu2O. The photoelectrochemical activity of the synthesized samples was evaluated using current-voltage measurements. The results suggest that the optimal electrolyte conditions for Cu2O synthesis were achieved at pH 13 and electrolyte temperature of 60°C.
Effect of morphology on the photoelectrochemical performance of nanostructured Cu 2 O photocathodes
Nanotechnology, 2021
Cu 2 O is a promising earth-abundant semiconductor photocathode for sunlight-driven water splitting. Characterization results are presented to show how the photocurrent density (J ph), onset potential (E onset), band edges, carrier density (N A), and interfacial charge transfer resistance (R ct) are affected by the morphology and method used to deposit Cu 2 O on a copper foil. Mesoscopic and planar morphologies exhibit large differences in the values of N A and R ct. However, these differences are not observed to translate to other photocatalytic properties of Cu 2 O. Mesoscopic and planar morphologies exhibit similar bandgap (e.g.) and flat band potential (E fb) values of 1.93 ± 0.04 eV and 0.48 ± 0.06 eV respectively. E onset of 0.48 ± 0.04 eV obtained for these systems is close to the E fb indicating negligible water reduction overpotential. Electrochemically deposited planar Cu 2 O provides the highest photocurrent density of 5.0 mA cm −2 at 0 V vs reversible hydrogen electrode (RHE) of all the morphologies studied. The photocurrent densities observed in this study are among the highest reported values for bare Cu 2 O photocathodes.
Journal of Solid State Electrochemistry, 2019
Cu2O is one of the most studied semiconductors for photocathodes in photoelectrochemical water splitting (PEC-WS). Its low stability is counterbalanced by good activity, provided that a suitable underlayer/support is used. While Cu2O is mostly studied on Au underlayers, this paper proposes Cu(0) as a low-cost, easy to prepare and highly efficient alternative. Cu and Cu2O can be electrodeposited from the same bath, thus allowing in principle to tune the final material's physicochemical properties with high precision with a scalable method. Electrodes and photoelectrodes are studied by means of electrochemical methods (cyclic voltammetry, Pb underpotential deposition) and by ex-situ X-ray absorption spectroscopy (XAS). While the potential applied for the deposition of Cu has no influence on the bulk structure and on the 2 photocurrent displayed by the semiconductor, it plays a role on the dark currents, making this strategy promising for improving the material's stability. Au/Cu2O and Cu/Cu2O show similar performances, the latter having clear advantages in view of future use in practical applications. The influence of Cu underlayer thickness was also evaluated in terms of obtained photocurrent.
IOP Conference Series: Materials Science and Engineering
We report the annealing effects on the morphological and structural properties of Cu2O films electrodeposited on Cu substrates from an aqueous solution containing copper acetate and lactic acid. The Cu2O/CuO layers has been constructed by electrodeposition of p-Cu2O layer on the modified surface of Cu substrate followed by formation of the CuO layer by annealing from 100ºC to 300ºC. The morphology and structural analysis was performed using optical microscope, AFM and XRD respectively. The result showed that increasing the annealing temperature resulted in the increment of the Cu2O grain size from about 96 to 201 nm. AFM reveals the precipitation of CuO grains on the Cu2O layer by annealing in air at 300ºC, and completely covered the surface of Cu2O layer.
Controlled growth of Cu2O thin films by electrodeposition approach
Materials Science in Semiconductor Processing, 2017
Thin films of Cu 2 O comprised of wavelike surface characteristic of compact nanoparticles were synthesized using a facile and cost-effective electrodeposition approach. The distinct surface morphologies with well-aligned crystal orientation were obtained through the controlled electrodeposition parameters. The high resolution AFM combined with the peak force AFM images mapped the nanomechanical and chemical properties of the Cu 2 O nanostructured films. The structural, optical, and compositional analyses of the as-deposited thin films show bulk Cu 2 O material. The electrodeposition approach could proceed non-intermittently under ambient conditions, and provides a facile and economic way of depositing thin films of Cu 2 O with wavelike characteristics. The photoluminescence lifetime was found be very short in the range of 0.8-1.3 ns for Cu 2 O films. The Mott-Schottky measurement exhibited p-type conductivity and carrier density was found to bẽ 2×10 18. The observed photoluminescence lifetimes, and carrier densities could help implementing the Cu 2 O films as an efficient hole-conducting, and photoelectrode materials in solar cells and water splitting devices.
Chemical Engineering Journal
We propose a simple way to increase incident photon-to-current conversion efficiency (IPCE, Y) for electrodeposited p-type Cu 2 O films through addition of Eu(III) to the electrodeposition bath. This is the first reported enhancement of photocurrent for Cu 2 O modified with a rare-earth element. Our study is based on hypothesis that a large ionic radius of Eu(III) promotes its precipitation in form of inclusions of another phase, which act as getter centers leading to purification of host material from detrimental impurities and, correspondingly, to increase in lifetime of non-equilibrium charge carriers. SEM, EDX and XRD analyses indicate that addition of Eu (III) results in some increase of Cu 2 O crystallite size and growth of a secondary Eu containing phase without changing the Cu 2 O lattice parameters. Electrochemical impedance spectroscopy indicates invariance of acceptor concentration and flat band potential for Eu modified films. Remarkable increase of charge carriers' lifetime,
ACS Applied Materials & Interfaces, 2015
In this paper, we demonstrate development of p-Cu 2 O thin films through cathodic electrodeposition technique at constant current of 0.1mA/cm 2 on Cu, Al and ITO substrates from basic CuSO 4 solution containing Triton X-100 as the surfactant at 30-35 o C. The optical and morphological characterizations of the semiconductors have been carried out using UV-vis spectroscopy, XRD, SEM and Raman spectroscopy. The band gap energy of ~2.1eV is recorded whereas SEM reveals that the surface morphology is covered with Cu 2 O semiconductors. XRD analyses confirm that with change in substrate, the size of Cu 2 O 'cubic' crystallites decreases from ITO to Al to Cu substrates. Photoelectrochemical characterizations
Properties Enhancement of Electrodeposit-n-Cu2O Thin Film by Annealing Treatment
The report is on analysis of the n-type cuprous oxide (n-Cu 2 O) thin film toward the effect of annealing duration. The n-Cu 2 O material is firstly accumulated on the glass substrate of fluorine-doped tin oxide (FTO) by approach of electrodeposition with deposition time of 30 minutes, with a 60°C of solution temperature and pH 6.5. The n-Cu 2 O sample is then undergoes an annealing treatment with duration ranged from 40 till 70 minutes with an 200ºCofannealing temperature. Next, effective properties of structural, morphology, topology, optical, electrical and photoelectrochemical of annealed n-Cu 2 O thin film were evaluate against the related instrument. From the characterization finding, 50 minutes possess to be the most suitable annealing time. With the implementation treatment of annealing, the n-Cu 2 O thin films properties were significantly enhanced. .
Jurnal Kejuruteraan, 2018
In the present study, cuprous oxide nanowire fabricated using wet chemical oxidation method was proven to produce high photoactive film for photoelectrochemical (PEC) water splitting. A relatively high photocurrent density of-5mA cm-2 at 0.6V vs Ag/AgCl was generated. The PEC performance is the reflection of intrinsic light absorption capacity at visible region which correspond to 2.0eV, an ideal band gap for PEC water splitting. Comparison with calculated data based on density functional theory using CASTEP shows that the band gap and light absorption capacity obtained from experimental work exhibited a close match. Hence, this study suggested that the preparation of Cu 2 O thin film via wet chemical oxidation method obeyed the theoretical prediction. However, the Cu 2 O is limited with poor stability in PEC condition attributed to the insufficient potential of its valence band to oxidize water. Therefore, an effort was directed to address the feasibility of shifting the valence band by modeling a doped Cu 2 O with several dopants using DFT technique. The selected dopants were Ag, Co, Ni and Zn. Preliminary conclusion of this study indicated that doping could be used to tune the band gap of Cu 2 O due to ionic radii of the dopant affected the shifting of band gap. In this study, Co showed more significant improvement of Cu 2 O for photoelctrochemical water splitting process. However, to validate the simulation, further study should be carried out experimentally.