Mn⁴⁺ Ions for Solid State Lighting

Phosphors activated with Mn⁴⁺ ion are gaining prominence in the field of solid-state lighting as generators of red photon. In the present review, we focus on several important points that are fundamentally important to produce a commercially useful phosphor. This includes an understanding of the Mn⁴⁺ energy levels in the free state and in the crystal fields and of the host dependent variations in the Mn⁴⁺ emission wavelength. Additionally, we formulate several practical recommendations on how to tune the emission wavelength and emission intensity of Mn⁴⁺-doped phosphors. The main spectroscopic parameters of the Mn⁴⁺ ion in more than 100 phosphor materials are collected and discussed.