Solar cells operating in harsh conditions such as extraterrestrial environment suffer from ionizing UV irradiation from the sun and radiation damages from high-energy particles. Titania (TiO2) can achieve high transmittance in the visible and near-infrared while efficiently blocking UV irradiations. Cerium-doped yttrium aluminum garnet (YAG:Ce) is commercially used as an efficient spectral downconverter in white-light LEDs, and it has also been studied for its potential as a radiation-withstanding scintillator. We propose TiO2∕YAG∶Ce thin films utilizing TiO2’s UV cut-off properties as well as YAG:Ce’s downshifting properties as both multipurpose protector and performance enhancer for solar cells.