Local Structure Modulation Induced Highly Efficient Red-Emitting Ba 2 Gd 1-x Y x NbO 6 :Mn 4+ Phosphors for Warm WLEDs

Modulating the crystal field environment around the emitting ions is an effective strategy to improve the luminescence performance of the practical effective phosphor materials. Here, smaller Y3+ ions were introduced into substituting the Gd3+ sites in Ba2GdNbO6:Mn4+ phosphor to modify the optical properties, including the enhanced luminescence intensity, red-shifted and longer lifetime of the Mn4+ ions. The substitution of smaller Y3+ ions leads to lattice contraction, and then strengthens pressure on the local structure, enhances lattice rigidity, and suppresses nonradiative transition. Moreover, the prototype pc-LED demonstrated a continuous change correlated color temperature (CCT, 4883-7876 K) and color rendering index (CRI, 64.1-83.2), suggesting that it can be a promising candidate as a warm red phosphor for WLEDs. Thus, the smaller-ion partial substitution can pave a concise approach to modulate the crystal field environment around the emitting ions for excellent luminescence properties of phosphors towards the modern artificial light.