Role of Ca2+ co-dopants on structural and optical properties of YF3:Tm3+/Yb3+ upconversion phosphor for improved optical thermometry

•The Ca2+ co-doping has affected the structural and optical properties of pure YF3:Tm3+/Yb3+ upconversion phosphor particle.•The effect of different concentration of Ca2+ co-doping on the structural and upconversion luminescence properties of pure YF3:Tm3+/Yb3+ has been studied comparatively.•Optical thermometry ability of present samples has been calculated and compared through sensor sensitivity measurement between two thermally coupled levels.