An analysis of DSSC performance based on nanosphere, nanorod, and nanoparticle anode morphologies

Abstract

The precise nature of dye-sensitized solar cell (DSSC) anodes plays a vital role in inter-particle contact, dye absorption, electrolyte diffusion, and distribution of sub conduction band states. This study compares the charge transfer dynamics at the oxide-dye-electrolyte interface in DSSC anodes composed of either nanoparticles (NPs), nanospheres (NSs), or nanorods (NRs). The crystallinity, morphology, visible light and dye absorption on the films were studied by XRD, SEM, and UV-Vis diffuse reflectance spectroscopy while the optoelectronic properties in the DSSC were evaluated by current–voltage, Incident photon to current conversion efficiency, and Electrochemical Impedance Spectroscopy (EIS) measurements. Visible light absorption was highest in NR films while NS films showed the highest light scattering. However, the DSSC with NP films showed the highest power conversion efficiency (PCE) that was attributed to increased dye adsorption amount. The DSSC with NS films had the least PCE but showed the highest Voc of 0.86 V. This high Voc was attributed to the high Fermi level, reduced charge recombination between the electrolyte and primary nanoparticles, and increased electrolyte diffusion within the nanospheres, as deducted from EIS measurements. The study suggests that the interparticle interaction and shape significantly influence the optoelectronic properties of DSSC anodes. The performance in this case was limited by dye absorption.