Abstract

Dye-sensitized solar cells (DSSCs) are promising alternative to traditional silicon based solar cells for converting light to electrical energy owing to their low cost and relatively high efficiency [1]. However, the traditional DSSCs make use of a liquid electrolyte containing the iodine/iodide redox couple as dye regenerating material, resulting in numerous practical problems related to physical stability due to the evaporation and leakage of liquid electrolyte and degradation of dye molecules [2]. Resultantly, the development of solid-state DSSC incorporating alternative materials to replace the liquid electrolyte has currently received tremendous interest. Devices composed of light absorbing semi-conducting polymers infiltrated into mesoporous metal oxide electrodes are remarkably similar to solid-state dye-sensitized solar cells, and in the most efficient form are a true “hybridization” of polymer and dye-sensitized solar cells with dual light absorption in both a surface absorbed dye and the polymer hole-transporter [3]. Recently, significant insight into the mechanisms of charge generation and recombination in interpenetrating networks of electron-rich donor polymers and electron-deficient acceptors used in bulk heterojunction organic solar cells has been gained through optical spectroscopy [4]. However, application of similar concept with solid-state DSSC structure is not straight-forward owing to the complexity involved in understanding the processes at organic-inorganic interfaces and in particular the presence of ionic environment to enhance the photovoltaic efficiencies [5].

© 2011 Optical Society of America