Iodine-modified Titania aerogel surface and crystal lattice: photon absorption in quasi-solid dye-sensitized solar cells sensitive to N719 dye

Abstract

This study thoroughly examines the effectiveness of iodine-based dopants in dye-sensitized solar that utilize titania aerogel by linking the material characteristics altered through the interaction of iodine with the surface and lattice structures. The surface-adsorbed iodine functionalized titania aerogel, designated as AI, while the lattice incorporated iodine and potassium ions in the titania aerogel and labeled it LI. The LI-based photoanode demonstrated an improved dye loading capacity of 0.43 µmol/mg and a significantly higher device efficiency of 4.34%, in contrast to the AI-based device, which achieved an efficiency of 1.66%. The spectroscopic analysis showed notable broadening and redshift in the absorption spectra for LI, suggesting robust electronic coupling and dye aggregation, which enhanced photon absorption and electron injection efficiency. Electrochemical impedance spectroscopy revealed a reduced charge transfer resistance (R_Ct = 29.5 Ω) and an increased electron lifetime (τ_n = 27.4 ms) for the LI-based DSSC, leading to enhanced interfacial charge transport and minimized recombination. The findings underscore the importance of the photoanode’s surface characteristics and the dyes’ aggregation for improving the performance of dye-sensitized solar cells. This study identifies LI-based photoanodes as strong contenders in enhancing the efficiency of DSSCs, offering valuable insights into optimizing charge dynamics and photochemical stability.