Designing high thermally stable deep red phosphors based on low thermal expansion coefficients for optical applications.

ABSTRACT

Mn4+-activated oxide phosphors with low cost and unique luminescent properties have been considered as a promising candidate for various optical applications, while the search for high thermal stable red-emitting phosphors is still a huge challenge. In our work, we find and unveil the relationship between luminescence thermal quenching behavior and thermal expansion coefficients (α/10-6 K-1) based on double-perovskite niobate phosphors Ca2LnNbO6Mn4+ (Ln3+ = Y3+, Gd3+, La3+, or Lu3+). It can be concluded that the phosphors with low thermal expansion coefficients contribute to high thermal stability. Subsequently, Ca2LuNbO6Mn4+ accomplishes accurate temperature testing and high-CRI white light-emitting diodes. Thus, a thermal expansion coefficient strategy is a new guide to select the appropriate substrate with high thermal stability for an Mn4+-activated emitter.