Effect of surface roughness of TiO 2 films on short-circuit current density of photoelectrochemical cell of ITO/TiO 2 /PVC-LiClO 4 /graphite Mohd. Yusri Abd. Rahman a, * , Muhamad Mat Salleh b , Ibrahim Abu Talib b , Muhamad Yahaya b a College of Engineering, Universiti Tenaga Nasional, 43009 Kajang, Selangor, Malaysia b Pusat Pengajian Fizik Gunaan, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia Received 4 February 2004; received in revised form 17 June 2004 Available online 22 September 2004 Abstract This paper reports the effect of surface topography of titanium dioxide films on short-circuit current density of photoelectro- chemical solar cell of ITO/TiO 2 /PVC-LiCLO 4 /graphite. The films were deposited onto ITO-covered glass substrate by screen-print- ing technique. The films were tempered at 300 °C, 350 °C, 400 °C, 450 °C and 500 °C for 30min to burn out the organic parts and to achieve the films with porous structure. The surface roughness of the films were studied using scanning electron microscope (SEM). Current–voltage relationship of the devices were characterized in dark at room temperature and under illumination of 100mWcm À2 light from tungsten halogen lamp at 50 °C. The device utilising the TiO 2 film annealed at 400 °C produces the highest short-circuit current density and open-circuit voltage as it posses the smoothest surface topography with the electrolyte. The short-circuit current density and open-circuit voltage of the devices increase with the decreasing grain size of the TiO 2 films. The short-circuit current density and open-circuit voltage are 0.6 lA/cm 2 and 109mV respectively. Ó 2004 Elsevier B.V. All rights reserved. PACS: 84.60.Fd Keywords: Photoelectrochemical cell; Screen-printing technique; Surface topography; Titanium dioxide 1. Introduction Transition metal–oxide semiconductor such as tita- nium dioxide has widely been used in photoelectrochem- ical cell [1]. This paper reports the use of titanium dioxide which is in film form [2,3] as a photoelectro- chemical cell material. This material has been chosen as solar cell as its fabrication cost is cheap, preparable in thin film form and non-toxic. In this work, titanium dioxide films were prepared onto ITO-covered glass sub- strate by screen-printing technique. The objective of this work is to study the effect of surface roughness of tita- nium dioxide films on the short-circuit current density and open-circuit voltage of photoelectrochemical of ITO/TiO 2 /PVC-LiClO 4 /graphite. The variation of sur- face roughness of the TiO 2 films can be obtained by var- ying their annealing temperature [4]. 2. Materials and methods ITO-covered glass substrate with a sheet resistance of 2 X/square underwent chemical cleaning using acetone and 2-propanol in ultrasonic bath. The TiO 2 paste 1567-1739/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.cap.2004.08.003 * Corresponding author. Tel.: +60 3 89287262; fax: +60 3 89263506. E-mail address: yusri@uniten.edu.my (M.Y.A. Rahman). www.elsevier.com/locate/cap Current Applied Physics 5 (2005) 599–602