Luminescence investigation of Eu3+–Sm3+ co-doped Gd2−x−y Eu x Sm y (MoO4)3 phosphors as red phosphors for UV InGaN-based light-emitting diode

Abstract: Gd2−x−y Eu x Sm y (MoO4)3 (x =0, 0.20, 0.40, 0.60, 0.80, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, and y =0, 0.020, 0.024, 0.028, 0.032, 0.036, 0.040) were prepared by solid-state reaction technique at 800°C and 950°C respectively; two types of host structure (monoclinic structure for 800°C and orthorhombic structure for 950°C) were obtained. The photo-luminescent results show that Gd0.372Eu1.6Sm0.028(MoO4)3 with orthorhombic structure exhibits the most intense red-emitting under near UV excitation. In the Eu3+–Sm3+ co-doped system, both Eu3+ and Sm3+ f–f transition absorptions are observed in the excitation spectra, the intensities of the main emission line (5D0 → 7F2 transition of Eu3+ at 615nm) are strengthened because of the energy transition from Sm3+ to Eu3+. With the broadened absorption around 400nm, strengthened emission intensity at 615nm and the appropriate chromaticity coordinates (x =0.65, y =0.33), the phosphor Gd0.372Eu1.6Sm0.028(MoO4)3 was combined with a ∼400nm emitting InGaN chip to obtain an intense red-emitting LED finally. [Copyright &y& Elsevier]