Photoluminescence properties of single-component white-emitting Ca9Bi(PO4)7:Ce3+,Tb3+,Mn2+ phosphors for UV LEDs

Abstract

Co-doping of Ce³⁺/Eu²⁺, Tb³⁺, Mn²⁺ ions into a single-component host is commonly used to achieve white-light phosphors through energy transfer, which present good color stability and high color rendering index (CRI) values. In this work, a series of single-component trichromatic white-light-emitting Ca₉Bi(PO₄)₇(CBPO):Ce³⁺,Tb³⁺,Mn²⁺ phosphors were synthesized and investigated. The crystal structure, luminescence properties and energy transfer behavior are discussed in detail. The energy transfer process from Ce³⁺ to Tb³⁺/Mn²⁺ has been demonstrated to be a resonant type via the dipole–dipole–quadrupole–quadrupole interaction mechanism, respectively, which makes the emission color shift from purple-blue to green/red with the corresponding Commission Internationale de L'Eclairage (CIE) chromaticity coordinates from (0.166, 0.011) to (0.260, 0.569) and (0.582, 0.287), respectively. Additionally, the white light emission by controlling the concentration ratio of Tb³⁺ and Mn²⁺ ions has been acquired in the CBPO:0.08Ce³⁺,0.22Tb³⁺,0.11Mn²⁺ sample with the CIE chromaticity coordinates of (0.375, 0.310) and an absolute quantum yield of 50% upon 292 nm excitation. The maximum quantum yield is 84% for CBPO:0.08Ce³⁺,0.90Tb³⁺. The good thermal stability of the CBPO:0.08Ce³⁺,0.22Tb³⁺,0.11Mn²⁺ sample shows about 83.6% at 150 °C of its initial PL intensity at room temperature, which attracts more attention. The results suggest that the present phosphors can be potentially applied as candidates of single-component white-light phosphors for UV-pumped w-LEDs.