A Lu3Sc2Ga3O12: Eu3+ red-emitting phosphor with excellent optical properties and thermal stability was obtained by partially replacing Lu3+ with Gd3+ / Y3.

ABSTRACT

A novel red phosphor Lu3(1-x)Sc2Ga3O12 xEu3+(0 ≤ x ≤ 0.3) was successfully prepared by high temperature solid state method. The Lu2.4Sc2Ga3O12 0.2Eu3+ phosphor shows strong high internal quantum efficiency and thermal stability with values of 64.79 % and 87.0 %, respectively. Based on Lu2.4Sc2Ga3O12 0.2Eu3+ phosphor, the partial replacement of Lu3+ ions in the host by Gd3+ / Y3+ ions changes the local crystal field environment of Eu3+ ions, resulting in wonderful changes in the luminous center, and the luminous intensity at 593 nm is increased by 3.66 and 3.54 times, respectively. The decay time of Eu3+ ions is analyzed from the perspective of dynamics, and the reasons for the enhancement of luminescence after partial replacement of Lu3+ ions are discussed in detail from two aspects of phosphor structure and crystal field effect around Eu3+ ions. In addition, with the substitution of Gd3+ / Y3+ ions, the thermal stability of the sample is 90.3 %/89.4 % with excellent low thermal quenching. The thermal quenching mechanism is described by combining Debye temperature and activation energy. The sample also has a high internal quantum efficiency IQE=79.03 % / 78.24 %. Finally, under the excitation of 365 nm chip, the phosphors of Lu2.34Sc2Ga3O12 0.2Eu3+, 0.02Gd3+ and Lu2.34Sc2Ga3O12 0.2Eu3+, 0.02Y3+ synthesized R-LED device has extremely high color rendering index, Ra is 78.23/77.15 and color temperature is 1640.38 K/1642.97 K. The experimental results show that the Lu2.34Sc2Ga3O12 0.2Eu3+, 0.02Gd3+ / Y3+ phosphors prepared has a wide application prospect in w-LED devices.