Investigation of 515Â nm green-light emission for full color emission LaAlO3 phosphor with varied valence Eu

► A white-light is achieved from valence-mixed Eu in full-color LaAlO3. ► A unique green-light emission at 515 nm is examined by spectrum and decay time. ► The energy transfer happens in between di- and tri- valent Eu and host as well. ► We propose the 5D2-7F3 transition for trivalent Eu leads to that green emission.