Effect of High Dielectric SrF2 in TiO2 photoanode for Dye-Sensitized Solar Cell Applications

Abstract

Dye-sensitized solar cells (DSSC) have been extensively investigated as promising candidate for solar energy conversion owing to their low cost, eco-friendly and high device efficiency. Among the other, photoanode is one of the key components in DSSC which defines its performance. Charge recombination and low light harvesting are the two major drawbacks of conventional TiO2 photoanode which limits the device efficiency. With this aim, the present work focused on the preparation of high dielectric SrF2 nanoparticles (ε’=6.844 x 106 at 1 Hz) and its study on incorporation with TiO2 photoanode with various weight percentages for device assembly. It can reduce the recombination by strong electrostatic shielding and increase the charge collection efficiency through interfacial polarization at dielectric-semiconductor interface shown in Fig.1. Improved power conversion efficiency (PCE) of 7.581% is obtained in 10 wt% SrF2:90 wt% TiO2 based photoanode which is 8.3% higher than the device efficiency of pure TiO2 based DSSC (6.997%). The interfacial charge transport kinetics of fabricated DSSCs are also explored using electrochemical impedance spectral (EIS) analysis. Low recombination resistance Rrec (49.9 Ω) in 10 wt% SrF2:90 wt% TiO2 based DSSC reveals the reduced recombination dynamics compared to other devices due to the optimized concentration of SrF2 incorporation in TiO2 photoanode for balancing charge injection and recombination. Keywords: DSSC; SrF2; Interfacial polarization; Dielectric constant and EIS Acknowledgement: This work was supported by Brain Pool Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT, Korea. (Grant number: 2019H1D3A1A01071183). It was also supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation, funded by the Ministry of Science, ICT & Future Planning (No: NRF-2016M1A2A2940912). Fi gure.1. Dielectric plot as a function of angular frequency (Inset shows interfacial polarization at dielectric-semiconductor interface). Figure 1