Mn²⁺and Mn⁴⁺red phosphors: synthesis, luminescence and applications in WLEDs. A review

Abstract

Transition-metal activated phosphors are an important family of luminescent materials that can produce white light with an outstanding color rendering index and correlated color temperature for use in light-emitting diodes.

A universal HF‐free synthetic method to highly efficient narrow‐band red‐emitting A2XF6:Mn4+ (A = K, Na, Rb, Cs; X = Si, Ge, Ti) phosphors

“…When Mn 4+ is incorporated into the octahedral lattice of the fluoride hosts, several sharp red emission peaks, with the maximum at ~630 nm, can be obtained under 460 nm blue light excitation . The full‐width at half maximum (FWHM) of 630 nm is only 3 nm, which is much narrower than that reported in Eu 2+ ‐doped phosphors . In addition, they also show high QE (~90%) and excellent thermal stability .…”

“…Recently, Mn 4+ ‐activated fluoride phosphors (eg, K 2 SiF 6 :Mn 4+ ) have gained considerable attentions because they are promising candidates as a red emission component in pc‐ｗLED backlights . When Mn 4+ is incorporated into the octahedral lattice of the fluoride hosts, several sharp red emission peaks, with the maximum at ~630 nm, can be obtained under 460 nm blue light excitation . The full‐width at half maximum (FWHM) of 630 nm is only 3 nm, which is much narrower than that reported in Eu 2+ ‐doped phosphors .…”

Manganese(II) Thiocyanate Complexes with Bis(phosphine Oxide) Ligands: Synthesis and Excitation Wavelength‐Dependent Multicolor Luminescence

“…At present, Mn II complexes and Mn II ‐doped solids attract great attention due to their unique photo‐ and electroluminescent properties, low cost, high stability and facile processability . The luminescence of these materials is originated by spin‐forbidden d – d transitions within Mn 2+ ion, has a phosphorescent character and covers the spectral range from ≈ 500 nm to near‐IR edge , .…”

Engineering cation vacancies to improve the luminescence properties of Ca14Al10Zn6O35: Mn4+ phosphors for LED plant lamp

“…Nevertheless, the Eu 2+ ‐doped phosphors are further hindered for indoor plant growth because rare‐earth materials are expensive and the far‐red region in the spectra is insufficient . Alternatively, Mn 4+ with 3d 3 electronic configurations can be excited effectively by blue light and exhibit far‐red emitting due to the spin‐forbidden 2 E → 4 A 2 transition . Many researches on Mn 4+ ‐doped phosphors mainly focus on fluorides and oxides.…”