Synthesis, crystal structure and luminescence characteristics of a novel red phosphor Ca19Mg2(PO4)14:Eu3+ for light emitting diodes and field emission displays

Abstract

In order to explore a new family of phosphate phosphors, the synthesis and crystal structure of a novel phosphate family, Ca₁₉M₂(PO₄)₁₄ (M = Mg, Zn, Mn), were investigated. Eu³⁺ doped Ca₁₉Mg₂(PO₄)₁₄ red phosphor was also successfully synthesized with the objective of application in ultraviolet-based light-emitting diodes (LEDs) and field emission displays (FEDs). The characteristic photoluminescence properties were studied in detail by photoluminescence excitation (PLE), emission (PL) spectra and decay times. The Ca₁₉Mg₂(PO₄)₁₄:0.06Eu³⁺ phosphor offers higher brightness and thermal stability than the commercial Y₂O₃:Eu³⁺. The unexpected temperature-dependent luminescence from higher ⁵D₁ states was observed and was explained via the configuration coordinate diagram. The cathodoluminescence (CL) spectra as a function of accelerating voltage and probe current were also measured. Excellent degradation properties with good color stability were obtained by continuous low-voltage electron-beam excitation of the phosphor. The results indicate that the phosphor Ca₁₉Mg₂(PO₄)₁₄:0.06Eu³⁺ can be a suitable red-emitting phosphor candidate for LEDs and FEDs.