A multiphase strategy for realizing green cathodoluminescence in 12CaO·7Al2O3–CaCeAl3O7:Ce3+,Tb3+ conductive phosphor

Abstract

A multiphase strategy is proposed and successfully applied to make the insulating green phosphor CaCeAl₃O₇:Tb³⁺ conductive in the form of 12CaO·7Al₂O₃–CaCeAl₃O₇:Ce³⁺,Tb³⁺. The phosphor shows bright green-light emission with a short lifetime (2.51 ms) under low-voltage electron beam excitation (3 kV). The green photo- and cathodoluminescence from ⁵D₄–⁷F_J (J = 6, 5, 4, 3) transitions of Tb³⁺ are significantly enhanced in comparison with pure C12A7:Tb³⁺. It was confirmed that this enhancement is the consequence of the joint effects of energy transfer from Ce³⁺ to Tb³⁺ and broadening of the absorption spectrum of Ce³⁺ due to the existence of multiple phases. In particular, under 800 V electron beam excitation, cathodoluminescence is improved by the modified electrical conductivity of the phosphor. When compared to the commercial Zn₂SiO₄:Mn²⁺ with a long luminescence lifetime of 11.9 ms, this conductive green phosphor has greater advantage for fast displays.