9 - Role of metal oxides as photoelectrodes in dye-sensitized solar cells

Abstract

The relentless demand for energy requires us to pursue it from renewable resources, and the resources should also be green and sustainable to avoid environmental issues. Dye-sensitized photo-electrochemical cells (DSPEC) have attracted considerable attention as a sustainable energy harvesting source among third-generation photovoltaics to increase electricity demand. DSPECs have notable benefits such as simple manufacturing procedures, being environmentally friendly and cost effective. Over the course of two decades, the development of DSPECs has been almost constant, owing to some constraints such as limited range absorption capacity, poor charge carrier transportation and collection defects, slow charge transfer process for oxidized dye regeneration, and poor long-term durability. The key challenge facing the scientific community is to boost the light-harvesting efficiency of DSPECs through utilizing various approaches, such as discovering new photoanode materials with appropriate nano-architectures dye-sensitized with promising metal oxide semiconductors and low expense solid-state electrolytes. This chapter emphasizes the photo-physics and morphology study of metal oxide as photoelectrode (anode and cathode) in the DSPECs, which involves charge recombination, collection, transportation, and separation. We outline the recent progress in the development of novel metal oxide materials for DSPEC. It also covers the effect of metal oxide materials, texture morphology, preparation and structure on the photovoltaic performance of DSPECs. The role of various metal oxides in n- and p-type DSPECs is also discussed.