A comparative study of Be and Mg ions adsorbed on TiO₂ photoelectrodes on interfacial charge recombination in solar cells

Be²⁺ and Mg²⁺ ions were adsorbed on a TiO₂ surface, and the resulting photoelectrodes were applied in dye-sensitized solar cells. Be²⁺ modification led to an increase in electron collection, electron injection, and dye regeneration efficiency, thereby increasing the short-circuit current. It was also found that the enhancements in both open-circuit voltage and fill factor of the device with Be²⁺-modified TiO₂ were due to the reduced charge recombination between the photoinjected electrons and I₃ ⁻. Be²⁺ modification resulted in an approximately 14% improvement in power conversion efficiency, whereas charge recombination was barely reduced in the case of Mg²⁺ modification.