Dye Sensitized Solar Cells Based On Metal-Free Organic Dyes and Aqueous Electrolytes

Dye-sensitized solar cells (DSCs) have recently emerged as promising candidates to utilize solar power because of their ease of fabrication and low cost as compared to conventional silicon based solar cells [1]. Till now, the most successful DSCs were obtained using porous TiO2 nanocrystalline film sensitized with a ruthenium based dye with an efficiency of 11%. However, a further increase in conversion efficiency is found to be limited by slow electron transport in porous TiO2 during the illumination. This requires replacement of TiO2 by other suitable semiconductor material. In this regard, ZnO is potential substitute for TiO2 in DSSC because of large band gap (3 eV), good electron affinity, and high electronic mobility (100 cm/Vs) [2].