The electronic structure and photoluminescence properties of Ca2GeO4:Eu3+ in ultraviolet and vacuum ultraviolet region

► Emission of Ca2GeO4:Eu3+ comprised of emissions of Eu3+ and host emission. ► Ca2GeO4:Eu3+ exhibited different colors such as red, pink, blue and purple. ► Excitation intensity of Ca2GeO4:Eu3+ at 466 nm was 1.7 times of that at 301 nm. ► Ca2GeO4:Eu3+ is a potential candidate applied in LEDs, PDPs or free-Hg lamps.