Full color control and white emission from CaZnOS:Ce3+,Na+,Mn2+ phosphors via energy transfer

Abstract

A series of CaZnOS:Ce³⁺,Na⁺,Mn²⁺ phosphors were successfully synthesized by a conventional solid-state reaction and their luminescence properties were investigated in detail. The phosphors can be excited by blue light at 455 nm, matching well with the commercial blue light emitting diode (LED) chips. Tunable full-color emission can be realized by combining the blue chips (455 nm), yellow emission (about 530 nm) ascribed to Ce³⁺ and red emission (about 590 nm) originating from Mn²⁺ in the CaZnOS host. Energy transfer (ET) from Ce³⁺ to Mn²⁺ in the CaZnOS host was validated by the variation of emission intensities as well as the decay lifetimes of Ce³⁺ ions with increasing Mn²⁺ concentration, and the ET mechanism is analyzed and ascribed to be a quadrupole–quadrupole interaction. The composition-controlled CaZnOS:0.03Ce³⁺,0.03Na⁺,0.03Mn²⁺ phosphor shows improved chromaticity characteristics fabricated using a blue LED chip, with an R_a of 82.5, a CCT of 5582 K and color coordinates (0.33, 0.32) at the forward current of 30 mA. We demonstrate that CaZnOS:Ce³⁺,Na⁺,Mn²⁺ show potential applications as a single-component white-light emission phosphor for fabricating white LED devices.