Improved phase stability of the metastable K2GeF6:Mn4+ phosphors with high thermal stability and water-proof property by cation substitution

Tunable‐spectrum Mn2+ doped garnet transparent ceramics for high‐color rendering laser lighting

“…In recent years, solid-state lighting has been considered as a new generation of light source, [1][2][3][4] which has been widely used in various lighting fields due to the advantages of high luminous efficiency, low energy consumption, environmental friendliness, and long service life. [5][6][7][8][9][10][11][12][13] For example, the commercial lighting emitting diodes (LEDs) normally use 460 nm blue light to excite Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce) yellow phosphor dispersed in epoxy or silicone to generate white light. 14,15 However, these organic materials have drawbacks of reduced luminous efficacy (LE), lower lifetime, shift of emission color, and reduced sensory comfort of human eyes due to the poor heat resistance and thermal conductivity (0.1-0.4 W•m -1 K -1 ).…”

“…In recent years, solid‐state lighting has been considered as a new generation of light source, 1–4 which has been widely used in various lighting fields due to the advantages of high luminous efficiency, low energy consumption, environmental friendliness, and long service life 5–13 . For example, the commercial lighting emitting diodes (LEDs) normally use 460 nm blue light to excite Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce) yellow phosphor dispersed in epoxy or silicone to generate white light 14,15 .…”

Improvement in luminescent properties and thermo-optical conversion mechanism of Na2SiF6:Mn4+,K+@GQDs

“…It is interesting that some of Mn 4+ -doped phosphors have good luminescent thermal stability at about 150 C, which is induced by their negative thermal quenching behavior. 12,[16][17][18] For example, the integrated emission intensity of K 2 SiF 6 :Mn 4+ coated with a thin Al 2 O 3 layer is about 104.6% of the initial value. 16 The integrated emission intensity of the K 2 (Ge 1Àx Si x ) F 6 :Mn 4+ (x ¼ 0.3) phosphor showed an enhancement at 152 C, which increased by 117% of the initial value.…”

“…12,[16][17][18] For example, the integrated emission intensity of K 2 SiF 6 :Mn 4+ coated with a thin Al 2 O 3 layer is about 104.6% of the initial value. 16 The integrated emission intensity of the K 2 (Ge 1Àx Si x ) F 6 :Mn 4+ (x ¼ 0.3) phosphor showed an enhancement at 152 C, which increased by 117% of the initial value. 17 The red-emitting phosphor Rb 2 TiF 6 :Mn 4+ was synthesized via the ion exchange method under mild conditions and exhibited a noteworthy luminescent enhancement with an increase in temperature, where its integrated emission intensity at 150 C was enhanced to about 120% of the initial value.…”

“…14 In conclusion, many achievements have been made in preparing Mn 4+ -doped uoride phosphors through H 2 O 2 -free methods. 14,16,26,27 In these methods, the activator K 2 MnF 6 (or Na 2 MnF 6 ) is obtained via the self-redox of KMnO 4 (NaMnO 4 ) in KF-HF solution, and H 2 XF 6 (X ¼ Ti, Si and Ge) is produced with XO 2 (X ¼ Ti, Si and Ge), Ti(OC 4 H 9 ) 4 and H 2 TiF 6 as raw materials. The nal products are BaXF 6 or A 2 XF 6 (A ¼ K, Na; X ¼ Ti, Si and Ge).…”