Photon management through titania architecture engineering in organic dye–Cu electrolyte dye sensitized solar cells

Abstract

Following the emergence of dye sensitized solar cells (DSSCs), considerable research attention has been devoted to further enhancing their performance through multiple approaches. Among those, enhancing light harvesting efficiency remains an effective route to augment the photocurrent generation and, consequently, the overall power conversion efficiency of DSSCs. Incorporation of scattering material layers on the photoanode layer has shown significant promise in this regard, especially with respect to N719 based DSSCs. Similar work with organic dye based DSSCs has been very scarce. Therefore, in this study, we have explored the morphology-dependent scattering effect of TiO₂ using three different structures, such as sphere-like particles (TS), novel twisted fiber-like structures (TF), and hierarchical flower-like architectures (TNF) in a DSSC configuration employing Y123 organic dye and a Cu-based redox shuttle. The structural, morphological, optical, and photoelectrochemical properties were analyzed to understand the crystalline properties, scattering efficiencies, and charge dynamics in the organic dye based DSSC device. Among the studied morphologies, TS exhibited the highest efficiency of 5.26% and a higher photocurrent density of 8.47 mA cm⁻², representing a 23.7% improvement in efficiency over the device without a scattering layer and 13.3% higher than the commercial scattering material. This enhancement is primarily attributed to efficient photon management, enabled by their superior light scattering ability compared to other structures. Our findings reveal that each morphology demonstrated unique contribution towards light scattering and charge dynamics under outdoor conditions. Interestingly, under indoor lighting, scattering effects were found to be negligible, providing new insights into morphology-specific light management in low light environments.