Journal of Alloys and Compounds 509 (2011) 5394–5399 Contents lists available at ScienceDirect Journal of Alloys and Compounds journal homepage: www.elsevier.com/locate/jallcom Photoelectrochemical investigations of cadmium sulphide (CdS) thin film electrodes prepared by spray pyrolysis A.A. Yadav ∗ , E.U. Masumdar Thin Film Physics Laboratory, Department of Physics, Electronics and Photonics, Rajarshi Shahu Mahavidyalaya, Latur, 413 512 M.S., India article info Article history: Received 19 December 2010 Received in revised form 27 January 2011 Accepted 12 February 2011 Available online 21 February 2011 Keywords: Energy storage materials Nanostructured materials Chemical synthesis Electrochemical reactions Photoconductivity and photovoltaics abstract Polycrystalline cadmium sulphide (CdS) thin films have been prepared by spraying a mixture of an equimolar aqueous solutions of cadmium chloride and thiourea on preheated fluorine doped tin oxide (FTO) coated glass substrates at different substrate temperatures. The cell configurations n- CdS/1 M (NaOH + Na 2 S + S)/C were used for studying the capacitance–voltage (C–V) characteristics in dark, current–voltage (I–V) characteristics in dark and under illumination, photovoltaic power output and spectral response characteristics of the as deposited thin films. Photoelectrochemical study shows that as deposited CdS thin films exhibits n-type of conductivity. The spectral response characteristics of the films at room temperature show a prominent sharp peak at 500 nm leading to optical bandgap energy of 2.48 eV. It is found that fill factor and efficiency are maximum for photoelectrode deposited at 300 ◦ C. This is due to low resistance; high flat band potential, maximum open circuit voltage as well as maximum short-circuit current. The measured values of efficiency () and fill factor (FF) are found to be 0.17% and 0.38 respectively for film deposited at 300 ◦ C. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Solar energy is one of the most promising energy sources in the future. Many researchers have concentrated on its utilization. Since Fujishima and Honda found a TiO 2 anode could split water into H 2 and O 2 under UV irradiation [1], which is considered as an important technique for solar energy storage and conversion, a variety of photoelectrochemical (PEC) solar cells have been fab- ricated and investigated for transformation of solar energy into electricity [2]. For the PEC solar cell, the primary requirement for good solar energy conversion is that the photocathode or photoan- ode should have band gap close to the maximum in the visible spectrum of solar light, besides its high stability in the electrolyte [3]. In recent years, considerable interest has been shown in the synthesis and photoelectrochemical test of semiconductor thin films due to the high conversion efficiency and low production cost [4]. The study of PEC solar cells fabricated by polycrystalline thin films of II–VI chalcogenide compound is interesting because of their excellent optoelectronic properties [5,6]. The II–VI semi- conductor compounds, particularly CdS, CdSe, CdTe, are of great interest because they are potential candidates in many practical applications like solar cells, optical detectors, dosimeters of ion- ized radiation, field effect transistors, and optoelectronic devices. ∗ Corresponding author. Tel.: +91 9975213852. E-mail address: aay physics@yahoo.co.in (A.A. Yadav). The performance of the devices based on CdS thin films depends on the structural and optoelectronic properties of the layers obtained under various experimental conditions [7,8]. Nanocrystalline cad- mium sulphide has attracted considerable attention because of its wide use in the fabrication of solar cells and optoelectronic devices [9–11]. Chemically deposited CdS thin films have been widely stud- ied in the last decade due to their potential applications. Most of these studies were devoted to the deposition mechanism and chemistry and only few to the investigations of physical properties. What commonly accepted is that the chemically deposited CdS thin films are nearly stoichiometric and exhibit a high photosensitivity (10 6 –10 9 ) [12]. Thus CdS is a technologically important material, especially for terrestrial utilization of solar energy. With its n-type semiconductor characteristics [13] and wide band gap (E g = 2.44 eV), thin films of CdS hold promise in photo- voltaic applications as window coatings in many types of solar cells with absorber materials. Electron hole pairs generated in CdS are well separated with electrons being highly localized. So it is the most studied nanocrystalline semiconductor because of its suitable bandgap, long lifetimes, important optical properties, excellent stability, easy fabrication and numerous device applications. The performance of polycrystalline semiconductor photoelectrochem- ical (PEC) solar cell depends to a large extent on the preparation of the thin film semiconductor electrode. Therefore the develop- ment of economical and effective synthetic method of CdS film is of importance in solar cell applications. In literature; variety of 0925-8388/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.jallcom.2011.02.061