TiO2/ZnO Nanocomposites with Metal-Free Dye and Polymer Gel Electrolyte: Optimizing Photovoltaic Efficiency and Assessing Stability by Time Series Analysis

Abstract

As part of the rapidly advancing field of energy technologies, solar energy-driven studies using nanomaterials have gained significant attention. In this context, designing dye-sensitized solar cells (DSSCs) with nanostructured titania (TiO2) and its composites is a key focus in material selection. This study investigates the synthesis and photovoltaic performance of TiO2 nanoparticles (NPs) and their composites with ZnO nanorods (NRs), synthesized via a one-step ex-situ approach. The devices were evaluated using a metal-free SK3 dye (D–π–A carbazole) and a Co2+/Co3+-based polymer gel electrolyte. Structural properties were analyzed using Rietveld refinement, alongside other physicochemical characteristics. Notably, the TiO2/ZnO nanocomposite (TZ-3 NCs) with 30 wt.% ZnO NRs in the photoanode demonstrated a significant improvement in solar energy conversion efficiency (η) of 4.3%, which is 1.8 times higher than the TiO2/SK3 NCs-based photoanode (2.38%). This enhancement is attributed to reduced charge transfer resistance, improved donor density, and increased surface area, facilitating efficient charge transport. Additionally, the study explored the stability of the TZ-3/SK3 NCs-based photoanode using time series analysis, a statistical tool that contributed to understanding its long-term performance.