Efficient sensitization of Mn2+ emission by Eu2+ in Ca12Al14O33Cl2 host under UV excitation

Abstract

A new blue-green emitting phosphor Ca₁₂Al₁₄O₃₃Cl₂:Eu²⁺,Mn²⁺ has been synthesized by the solid-state reaction technique method under a reductive atmosphere. The X-ray diffraction measurement results indicate that the crystal structure of the phosphor is a single phase of Ca₁₂Al₁₄O₃₃Cl₂. The phosphors can be efficiently excited by near ultraviolet (n-UV) light and show a blue emission band at about 450 nm and a green emission band at about 550 nm, which originated from the Eu²⁺ ions and the Mn²⁺ ions. The efficient energy transfer from the Eu²⁺ ions and the Mn²⁺ ions was observed and its mechanism should be a resonant type via a nonradiative dipole–quadrupole interaction. The critical distance between the Eu²⁺ ions and Mn²⁺ ions has been calculated to be about 10.83 Å as well. In addition, the temperature dependent photoluminescence of the as-prepared phosphors has been investigated in detail. Our results indicate that the developed phosphor may be used as a potential blue-green emitting phosphor for UV-based white LEDs.