title: 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.
authors.affiliation: Department of Chemistry, Indian Institute of Engineering Science & Technology (IIEST) , Shibpur, Howrah 711 103, West Bengal, India.
authors.forename: Sanjib
authors.initials: S
authors.lastname: Shyamal
authors.affiliation: Department of Chemistry, Indian Institute of Engineering Science & Technology (IIEST) , Shibpur, Howrah 711 103, West Bengal, India.
authors.forename: Paramita
authors.initials: P
authors.lastname: Hajra
authors.affiliation: Department of Chemistry, Indian Institute of Engineering Science & Technology (IIEST) , Shibpur, Howrah 711 103, West Bengal, India.
authors.forename: Harahari
authors.initials: H
authors.lastname: Mandal
authors.affiliation: Corrosion & Surface Engineering CSIR, National Metallurgical Laboratory , Jamshedpur 831007, India.
authors.forename: Jitendra Kumar
authors.initials: JK
authors.lastname: Singh
authors.affiliation: Analytical Chemistry Division, Bhabha Atomic Research Centre , Trombay, Mumbai 400085, India.
authors.forename: Ashis Kumar
authors.initials: AK
authors.lastname: Satpati
authors.affiliation: Birla Institute of Technology & Science (BITS) , Pilani 333031, Rajasthan, India.
authors.forename: Surojit
authors.initials: S
authors.lastname: Pande
authors.affiliation: Department of Chemistry, Indian Institute of Engineering Science & Technology (IIEST) , Shibpur, Howrah 711 103, West Bengal, India.
authors.forename: Chinmoy
authors.initials: C
authors.lastname: Bhattacharya
keywords: action spectra; cathodic electrodeposition; electrochemical impedance spectroscopy; ohmic conductivity; photoelectrochemical reduction of water; semiconductor photoelectrochemistry