Structure, luminescence properties and anti-thermal quenching of a novel Eu3+-activated red phosphor based on the negative thermal expansion material In0.5Sc1.5(MoO4)3

A new Eu3+-doped phosphor was synthesized by the high-temperature solid-state method based on In0.5Sc1.5(MoO4)3 with negative thermal expansion characteristics in the wide temperature range. The phosphor was pure phase, and the Eu3+ occupied the Sc3+-site. The main emission peak of the phosphor was located at 615 nm, which was attributed to the 5D0-7F2 energy level transition of Eu3+, and the fluorescence lifetime was between 297 and 493 μs. Its quenching concentration was 8 mol%, and the non-radiative energy transfer mechanism between Eu3+ ions was mainly exchange interaction. Under the excitation of 246 nm, the luminous intensity of phosphor was thermically enhanced after 348 K and showed near-zero thermal quenching characteristic. It could be attributed to the positive thermal expansion of phosphor change into two-dimensional negative thermal expansion. At 465 nm excitation, it also exhibited the anti- thermal quenching property and the luminous intensity remained 103.4 % at 423 K of that at the room temperature. The internal quantum efficiency of In0.5Sc1.5(MoO4)3: 8 mol% Eu3+ phosphor was 57.8 %, while the overall color purity was as high as 99.52 %. The LED device packaged it with a commercial LED chip could emit bright red light. Its comprehensive luminous properties were better than the commercial red phosphor Y2O3: Eu3+. The results showed that In0.5Sc1.5(MoO4)3: Eu3+ was a new red phosphor with good luminous performance and anti-thermal quenching characteristic.