Design the green emitting phosphor Ca9La(PO4)7:Eu2+ by the structural modulation and its application to white LEDs

A series of Ca9-xMxLa(PO4)(7):Eu2+ (M = Sr2+, Ba2+) phosphors were synthesized by the high temperature solid-state method, among which Ca9La(PO4)(7):Eu2+ (CLP:Eu2+) has a spectral emission range of 400-700 nm at the excitation wavelength of 330 nm. By using Sr2+ and Ba2+ to partially replace Ca2+ in the matrix to control the crystal field environment around Eu2+, the half-peak width of the spectrum is widened and the emission center is redshifted about 10 nm. When Ca2+ is replaced by Sr2+, the broadening of the spectrum is caused by the distortion of the lattice, but the difference is that when Ca2+ is replaced by Ba2+, the broadening of the spectrum is caused by the different redshift rates of the three luminous centers. This study provides a new idea to regulate the luminescence of Eu2+ by regulating the matrix composition and inducing potential luminescence centers in the matrix.