Luminescent thermal behavior of Eu3+ in K5Bi(MoxW1-xO4)4 phosphors

Abstract

From the practical point of view, the luminescent thermal behavior of phosphors is an important factor. In this work, two factors are found to influence the thermal quenching behavior of Eu3+ in a series of Eu3+ doped K5Bi(MoxW1-xO4)4 solid solution phosphors. These factors are the energy of the charge transfer state (CTS) and the thermal ionization process. With the introduction of Mo in the host matrix, the energy of CTS decreases, and the thermal ionization process is enhanced, which leads to a deterioration of thermal stability in solid solution phosphors. The thermal stability is improved by increasing the doping content of Eu3+, which may correlate to the weakening of the thermal ionization process. The K5Bi0.7(Mo0.5W0.5O4)4:0.3Eu phosphor possesses favorable color stability and color purity at high temperatures. Meanwhile, such phosphor matches well with a 365 nm LED chip and exhibits intense and pure red emission at a drive current of 200 mA.