Function of photoanode: Charge transfer dynamics, challenges, and alternative strategies

The monolayer of dye molecules on the photoanode functions like chlorophyll in plants and absorbs the incident light to generate both positive and negative charge carriers in the cell. This chapter discusses the composition of dye-sensitized solar cell (DSSC), the photoanode in particular, and the function of the photoanode. It also discusses the charge transfer dynamics and parameters influencing the photoconversion efficiency. The chapter explains several processes such as charge generation, charge separating, electron diffusion, charge recombination, and their mechanisms which are very much essential to understand the working principle of DSSC. It also suggests the challenges in the above-said processes and the strategies to overcome. The overall performance of the DSSCs is determined by three core elements, namely metal oxide, dye sensitizer, and metal oxide/dye/electrolyte interface. A lot of attention is devoted to research these elements in order to engineer suitable DSSC composition toward obtaining high photoconversion efficiency.