Investigation on short–circuit current density (Jsc) in the dye-sensitized solar cells by optimizing photoelectrode thickness

The photoelectrode of dye-sensitized solar cells (DSSC) is a vital part that loads the dye, transports the generated photoelectrons to the external load, and serves as an interface between the current collector and the dye. The performance of the DSSCs is highly influenced by the thickness of the photoelectrode. The short-circuit current density (Jsc) of the DSSC increases with thickness and reaches its maximum at a particular thickness, after which Jsc decreases and saturates. A theoretical approach is formulated, using which the optimal thickness required to obtain maximum Jsc for the DSSC is calculated. A novel analytical expression for optimal diffusion length (L0), which is the electron diffusion length required to maximize Jsc is derived. The experimental validation of the simulated results is carried out with DSSCs of varying photoelectrode thickness. These validation results suggest that this theoretical approach to determine the optimal thickness of photoelectrodes enhances the efficiency of dye-sensitized solar cells.