Effect of Substrates on the Photoelectrochemical Reduction of Water over Cathodically Electrodeposited p-Type Cu₂O Thin Films

Abstract

In this study, we demonstrate development of p-Cu2O thin films through cathodic electrodeposition technique at constant current of 0.1 mA/cm(2) on Cu, Al, and indium tin oxide (ITO) substrates from basic CuSO4 solution containing Triton X-100 as the surfactant at 30-35 °C. The optical and morphological characterizations of the semiconductors have been carried out using UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. The band gap energy of ∼2.1 eV is recorded, whereas SEM reveals that the surface morphology is covered with Cu2O semiconductors. XRD analyses confirm that with change in substrate, the size of Cu2O "cubic" crystallites decreases from ITO to Al to Cu substrates. Photoelectrochemical characterizations under dark and illuminated conditions have been carried out through linear sweep voltammetry, chronoamperometry and electrochemical impedance spectroscopic analysis. The photoelectrochemical reduction of water (H2O → H2) in pH 4.9 aqueous solutions over the different substrates vary in the order of Cu > Al > ITO. The highest current of 4.6 mA/cm(2) has been recorded over the Cu substrate even at a low illumination of 35 mW/cm(2), which is significantly higher than the values (2.4 mA/cm(2) on Au coated FTO or 4.07 mA/cm(2) on Cu foil substrate at an illumination of 100 mW/cm(2)) reported in literature.

Eu modified Cu2O thin films: Significant enhancement in efficiency of photoelectrochemical processes through suppression of charge carrier recombination

“…As a consequence, the reported values of quantum efficiency for the photocathodes based on the electrodeposited Cu 2 O films are usually significantly less than 100% (≈1% [24], ≈26% [28], ≈70% [20]) making relevant a looking for methods of charge recombination suppression. Our previous studies have demonstrated that properties of the electrodeposited Cu 2 O films can be improved by variation of electrolyte composition [35,36]. Nevertheless, origins of these effects are not completely understood and require further research.…”

Highly Photoactive and Photo-Stable Spray Pyrolyzed Tenorite CuO Thin Films for Photoelectrochemical Energy Conversion

“…Majority of the recently reported investigations are focused on Cu 2 O. [25][26][27][28][29][30][31][32] Due to the chemical instability and poor electron transfer, its nano-composites with other oxides or metal catalysts have been attempted. [33][34][35] On the other hand, CuO is chemically more stable than Cu 2 O but there are only few studies on the PEC response of CuO have been reported so far.…”

Donor/Acceptor-Induced Ratiometric Photoelectrochemical Paper Analytical Device with a Hollow Double-Hydrophilic-Walls Channel for microRNA Quantification

“…The prominent characteristic peak at 218 cm −1 was assigned to the second-order Raman-allowed mode (2Γ 12 − ) of Cu 2 O. 28 The peak at 148 cm −1 could be ascribed to Raman scattering from phonons of symmetry (Γ − 15 ), 29 whereas the relatively weak peaks at 308, 416, and 515 cm −1 matched well with the second-order overtone mode, fourphonon mode (3Γ 12 − + Γ 25 − ), and Raman-allowed mode, respectively. 25,28 A shoulder peak at 635 cm −1 was marked to the infrared-allowed mode.…”