Broadening light absorption and reducing recombination in DSSCs with Eu-doped BaTiO3@CaF2/TiO2 hybrid systems

Abstract

This work explores the synthesis and application of Eu-doped BaTiO₃@CaF₂ particles as hybrid photoabsorbers in TiO₂-based Dye-Sensitized Solar Cells (DSSCs) to enhance photovoltaic performance. The Eu-doped BaTiO₃@CaF₂ particles were synthesized using a microwave-assisted hydrothermal method at low temperature. Characterization techniques, including AFM, optical absorption, SEM, XRF, EIS, and J-V curve analyses, demonstrated that the hybrid material broadens light absorption to wide wavelengths, improving photon harvesting from solar radiation and aligning well with the absorption range of N-3 dyes. The difference in conduction band edges between BaTiO₃@CaF₂ and TiO₂ promotes efficient charge separation, reduces recombination, and facilitates directional electron transport, resulting in an open-circuit photovoltage of up to V_oc = 782 mV. The maximum short-circuit photocurrent density (J_sc = 7.12 mA/cm²) was achieved with two TiO₂ blocking layers, with a great fill factor of 0.59 and an efficiency of 2.94 %. The synergistic interaction of the photoactive layers reduced electronic recombination at the cell interfaces, with superior charge accumulation due to enhanced surface roughness, as evidenced by EIS and AFM measurements. These promising results confirm the potential of the Eu-doped BaTiO₃@CaF₂ hybrid photoabsorber for advanced solar cell applications, encouraging further optimization of TiO₂ and BaTiO₃@CaF₂ configurations to boost performance under diverse conditions.