Ca2YHf2Al3O12:Ce3+,Mn2+: energy transfer and PL/CL properties of an efficient emission-tunable phosphor for LEDs and FEDs

Abstract

It is of great significance for white light-emitting diodes (wLEDs) to explore new, efficient and stable inorganic phosphors excited by wideband near-ultraviolet (n-UV) light. A new type of efficient emission-tunable Ce³⁺/Mn²⁺ doped Ca₂YHf₂Al₃O₁₂ (CYHAO) garnet phosphor which can be excited by n-UV light is studied in this work. Due to the effective energy transfer (ET) from Ce³⁺ to Mn²⁺ in CYHAO, CYHAO:0.09Ce³⁺,xMn²⁺ phosphors have a wide excitation band in the 370–470 nm region with a peak at 410 nm. Under excitation at 410 nm, all the samples show tunable color emission and match with the near UV chip. Through the decay time, it is determined that the energy transfer efficiency is as high as 88.83%. The calculated activation energy is about 0.217 eV, indicating the relatively good thermal stability. The cathodoluminescence (CL) properties show that the phosphor has a high saturation current and saturation voltage. A single component white LED is fabricated by using the CYHAO:0.09Ce³⁺,0.3Mn²⁺ phosphor and a 400 nm n-UV chip. It is worth noting that the detailed study of the energy transfer mechanism, thermal quenching mechanism and CL mechanism has reference value for the development of new co-doped phosphors.