Insight into Interface Engineering at TiO₂/Dye through Molecularly Functionalized Caf1 Biopolymer

Abstract

The fast charge recombination kinetics and poor sensitizing ability in dye-sensitized solar cells (DSSCs) result in a significant electron loss and performance degradation. However, the retarding of electron recombination and/or increasing light-harvesting efficiency (LHE) via employing an appropriate interface modifier in DSSCs has rarely been investigated. Here, we firstly report a molecularly engineered Caf1 protein (both in monomeric and polymeric forms) to modify the surface states by effectively shielding the unfavorable reactions and improve the light absorption properties by introducing alternative anchoring facilities. Using this novel Caf1bio-polymer with high thermal stability (even at 90 o C), we achieved an unprecedented efficiency of 8.31% under standard illumination test conditions and maintain the output performance even under prolonged irradiation. Time-resolved fluorescence spectroscopy measurement reveals an improved electron transfer rate (k ET = 0.26 to 0.98×10 8 s -1 ), whereas V oc decay rate is lower (70% decay in 90 s) for Caf1-P@TiO 2 based cell than that of bare one (~85% decay in <10 s). We attributed this trend to the presence of chains in bio-polymer structure and the enhanced population of binding facilities with sensitizer molecules, promoting rapid charge transfer into TiO 2 and enhanced dye-loading capability. Our results shed light on the interface engineering and this novel Caf1bio-polymer offers a meaningful transfer of energy to develop efficient electrochemical cells with attractive properties for scale up and practical applications.

Zinc Stannate (Zn2SnO4)-Based Hybrid Composite Photoanode for Dye-Sensitized Solar Cell Application

“…It is also apparent that the pristine ZTO- and standard TiO 2 -based DSSC devices show a lower lifetime value, indicating low recombination resistance at the photoanode–electrolyte interface and decreasing carrier density. The J–V and EIS results obtained using ZTO, ZTO-ZnO, and ZTO-SnO 2 photoanode-based DSSC devices are compared with standard TiO 2 -based DSSC devices reported in the literature and summarized in Table . ,− Recently, Siwatch et al reported that the structured ZnO core provides a better electron transport pathway while the Zn 2 SnO 4 shell suppresses recombination by introducing an energy barrier between the core and oxidized dye or the electrolyte . Similarly, Li et al reported that the hierarchical SnO 2 /Zn 2 SnO 4 composite exhibits a maximum efficiency of 4.91% due to a large specific surface area and many active adsorption/interaction sites leading to higher light harvesting .…”

Impact of dopant ratio on the energy harvesting activity of polyaniline modified counter electrodes for Pt‐free dye‐sensitized solar cells

“…The high‐frequency intercept on the real axis represents the series resistance (R s ) of the electrode which describes mainly the resistance of the two identical electrodes and the electrolytic resistance. [ 55,66 ]…”

“…The high-frequency intercept on the real axis represents the series resistance (R s ) of the electrode which describes mainly the resistance of the two identical electrodes and the electrolytic resistance. [55,66] We mainly emphasize on the R s and R ct of CEs. The R s and R ct parameters of these electrodes have been obtained by fitting the experimental data using a Randles-type equivalent circuit in Autolab impedance analyzer shown as an inset in Figure 9.…”

Design of an amorphous ZnWSe2 alloy-based counter electrode for highly efficient dye-sensitized solar cells

“…[6][7][8][9] Among these PV technologies, DSSCs are a promising alternative to silicon solar cells in terms of low-cost raw materials, a facile fabrication process, and an extensive repertoire of materials. 10,11 Since the first report by O'Regan & Gratzel in 1991, the power conversion efficiency (PCE) of DSSCs has increased significantly above 15%. The DSSC industry has embraced a continuous effort in efficiency improvement and increasing attention in research through the engineering of materials, layers, and architectures.…”