Quantitative analysis of UV excitation bands for red emissions in Pr3+-doped CaTiO3, SrTiO3 and BaTiO3 phosphors by peak fitting

A quantitative spectral analysis of the ultraviolet (UV) broad excitation bands, which are located in the range 300-400 nm, for red emissions at around 610 nm in Pr-doped CaTiO3, SrTiO3:Al and BaTiO3:Mg phosphors has been carried out using a peak fitting technique. The obtained results demonstrate that the UV broad band of CaTiO3:Pr consists of four primary excitation bands centered around 330, 335, 365 and 380 nm and those of both SrTiO3:Al and BaTiO3:Mg consist of three primary bands centered around 310, 345 and 370 nm. Based on the behavior patterns and the values of the respective primary excitation bands' parameters, i.e. center gravity (λtop), maximum height (Imax) and full-width at half-maximum (FWHM), the UV-to-red relaxation processes in these titanate phosphors can be explained to be essentially the same, except for the existence of an additional relaxation pathway via electron-trap states in CaTiO3:Pr, which gives a characteristic shape of its UV excitation spectrum in the wavelength range of >360 nm.