Erbium-doped barium titanate (BaTiO₃:Er) xerogel film with a thickness of about 500 nm was formed on the porous strontium titanate (${\text{SrTiO}}_3)$ xerogel film on Si substrate after annealing at 800${}^{\circ }$C or 900${}^{\circ }$C. The elaborated structures show room temperature upconversion luminescence under 980 nm excitation with the photoluminescence (PL) bands at 523, 546, 658, 800 and 830 nm corresponding to ²${\text{H}}_{11/2}\to$⁴${\text{I}}_{15/2}$, ⁴${\text{S}}_{3/2}{\to }^4$${\text{I}}_{15/2}$, ⁴${\text{F}}_{9/2}{\to }^4$${\text{I}}_{15/2}$ and ⁴${\text{I}}_{9/2}\to$⁴${\text{I}}_{15/2}$ transitions of trivalent erbium. Raman and X-ray diffraction (XRD) analysis of BaTiO₃:Er\porous SrTiO₃\Si structure showed the presence of perovskite phases. Its excellent up-conversion optical performance will greatly broaden its applications in perovskite solar cells and high-end anti-counterfeiting technologies.Erbium-doped barium titanate (BaTiO₃:Er) xerogel film with a thickness of about 500 nm was formed on the porous strontium titanate (${\text{SrTiO}}_3)$ xerogel film on Si substrate after annealing at 800${}^{\circ }$C or 900${}^{\circ }$C. The elaborated structures show room temperature upconversion luminescence under 980 nm excitation with the photoluminescence (PL) bands at 523, 546, 658, 800 and 830 nm corresponding to ²${\text{H}}_{11/2}\to$⁴${\text{I}}_{15/2}$, ⁴${\text{S}}_{3/2}{\to }^4$${\text{I}}_{15/2}$, ⁴${\text{F}}_{9/2}{\to }^4$${\text{I}}_{15/2}$ and ⁴${\text{I}}_{9/2}\to$⁴${\text{I}}_{15/2}$ transitions of trivalent erbium. Raman and X-ray diffraction (XRD) analysis of BaTiO₃:Er\porous SrTiO₃\Si structure showed the presence of perovskite phases. Its excellent up-conversion optical performance will greatly broaden its applications in perovskite solar cells and high-end anti-counterfeiting technologies.