Investigation of (Eu2+)–(Mn2+) Energy Transfer and Y2O3 Scattering Effects in Phosphor-Converted White LEDs

Abstract

Phosphor-converted white light-emitting diodes (WLEDs) require both efficient luminescence conversion and effective control of photon propagation within the phosphor layer. Eu²⁺–Mn²⁺ co-doped phosphors are of interest because Eu²⁺ can act as a sensitizer for Mn²⁺ through an energy-transfer process. In addition, scattering materials can modify photon propagation and consequently affect the optical performance of WLEDs. This work discusses the Eu²⁺→Mn²⁺ energy-transfer process in Ba₂MgSi₂O₇ (BMSO) phosphors based on previously reported spectroscopic and mechanistic studies, while experimentally examining the effect of Y₂O₃ scattering conditions on WLED optical characteristics. The effects of Y₂O₃ on correlated color temperature (CCT), ΔCCT, and luminous output are analyzed, and its scattering properties are compared with those of KBr and TiO₂. The results show that Y₂O₃ produces a moderate scattering effect and influences both color characteristics and luminous output. The Y₂O₃-based WLED exhibits a CCT of 3000 K, a ΔCCT of 48.82 K, a CRI of 56.32, a CQS of 42.46, and a luminous output of 73.11 lm. Compared with the investigated scattering materials, TiO₂ provides stronger scattering and higher luminous output, whereas Y₂O₃ provides a more moderate scattering response with warm-white emission characteristics. The discussion of Eu²⁺–Mn²⁺ energy transfer and Y₂O₃ scattering provides complementary perspectives on luminescence conversion and photon propagation in phosphor-converted WLED systems.