International Journal of the Physical Sciences Vol. 6 (22), pp. 5190-5201, 2 October, 2011 Available online at http://www.academicjournals.org/IJPS ISSN 1992 - 1950 ©2011 Academic Journals Full Length Research Paper Dyed sensitized solar cells: A technically and economically alternative concept to p-n junction photovoltaic devices Nwanya, A. C. 1 , Ezema, F. I. 2 and Ejikeme, P. M. 3 * 1 National Centre for Energy Research and Development, University of Nigeria, Nsukka, Nigeria. 2 Department of Physics and Astronomy, University of Nigeria, Nsukka, Nigeria. 3 Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, Nigeria. Accepted 6 July, 2011 Nanocrystalline dyed sensitized solar cells (DSSC) are photo-electrochemical cells based on principles similar to the processes in natural photosynthesis. They are based on photo sensitization of nanocrystalline semiconductor electrodes by absorbed dyes. The DSSC provides a technically and economically credible alternative concept to present day p–n junction photovoltaic devices. The DSSC work on a different principle, whereby the processes of light absorption and charge separation are differentiated. This is in contrast to the conventional systems where the semiconductor assumes both the task of light absorption and charge carrier transport. In the DSSC, the bulk of the semiconductor is used solely for charge transport; the photoelectrons are provided from a separate photosensitive dye. Charge separation occurs at the surfaces between the dye, semiconductor and electrolyte. This paper introduces the structure and operating principles of dye sensitized solar cells (DSSC). The key components including the semiconductor oxides, conducting substrates, the dye sensitizers, the electrolytes and the counter electrodes used in dye sensitized solar cell was reviewed in details. The result of various researches done especially to improve the performance and the conversion efficiency of the dye cell was presented. Hence this paper reviews the progress which has been made and the mechanism involved in the operation of dye sensitized solar cell. Key words: Dye sensitized solar cell, nanocrystalline oxide semiconductor, counter electrodes, electrolytes, dyes. INTRODUCTION The sun’s energy is the primary source for most forms of energy found on the earth. Solar energy is clean, abundant and renewable, hence holds a tremendous potential to benefit our world by diversifying our energy supply, reducing our dependence on fossil fuels, improving the quality of the air we breathe and stimulating our economy. It is no longer news that in order to reduce our over dependence on fossil fuels, renewable sources of energy must be employed. Sunlight on earth drives the wind, fills hydroelectric reservoirs with rainwater and produces heat, light and biomass. *Corresponding author. E-mail: ejikemepaul13@yahoo.com. Hydropower is the major source of electricity consumed in the country contributing about 32% of the total installed commercial capacity (Ismaila, 2006). With the fluctuations and outages in the supply of this electricity, there is need to tap into other renewable sources of energy. To date, many of the solar energy systems are significantly more expensive than the traditional options available to customers (e.g. engines, gas heaters and grid electricity) in the short term. The cost, performance and convenience of these systems must be improved if solar energy is to compete in energy markets against more traditional alternatives. Large scale solar technologies like the solar photovoltaic system is yet to compete with the conventional energy systems. The biggest problem with the conventional approach is cost;