Co‐precipitation synthesis and luminescence properties of K₂TiF₆:Mn⁴⁺ red phosphors for warm white light‐emitting diodes

Abstract

K2TiF6:Mn(4+) red phosphors with different Mn(4+) doping concentrations were obtained using the co-precipitation method. X-Ray diffraction, scanning electron microscopy, Raman spectra, Fourier transform infrared spectroscopy, photoluminescence excitation and emission spectra and decay curves were used to characterize the properties of K2TiF6:Mn(4+) phosphors. Under excitation at 470 nm, an intense red emission peak around 631 nm corresponding to the (2)E(g)-(4)A2 transition of Mn(4+) was observed for 2.48 mol% K2TiF6:Mn(4+) phosphors and was used as the optimum doping concentration. The excellent luminescent properties of K2TiF6:Mn(4+) suggest that this material might be a promising red phosphor for generating warm white light in phosphor-converted white light-emitting diodes.

Control of Luminescence by Tuning of Crystal Symmetry and Local Structure in Mn4+‐Activated Narrow Band Fluoride Phosphors

“…Compared with five phonon sidebands (PSs), ZPL is much more sensitive to the local coordinated environment. Thus, the ZPL has very low intensity in the most popular fluoride phosphors, such as K 2 SiF 6 :Mn 4+ and K 2 TiF 6 :Mn 4+ . Nevertheless, most of the studies on Mn 4+ doped fluoride phosphors have focused on the synthesis of new compounds or different synthesis methods.…”

“…Thus,t he ZPL has very low intensity in the most popular fluoride phosphors,such as K 2 SiF 6 :Mn 4+ and K 2 TiF 6 :Mn 4+ . [12][13][14] Nevertheless,most of the studies on Mn 4+ doped fluoride phosphors have focused on the synthesis of new compounds or different synthesis methods.W hile the behavior of ZPL is rarely studied deeply and systematically,a nd the correlation between the local coordination environment and luminescent behavior remains obscure.…”

Control of Luminescence by Tuning of Crystal Symmetry and Local Structure in Mn4+‐Activated Narrow Band Fluoride Phosphors

“…Compared with five phonon sidebands (PSs), ZPL is much more sensitive to the local coordinated environment. Thus, the ZPL has very low intensity in the most popular fluoride phosphors, such as K 2 SiF 6 :Mn 4+ and K 2 TiF 6 :Mn 4+ . Nevertheless, most of the studies on Mn 4+ doped fluoride phosphors have focused on the synthesis of new compounds or different synthesis methods.…”

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

“…In addition, they also show high QE (~90%) and excellent thermal stability . To date, the fluoride‐based phosphors have been extended from A 2 X F 6 : Mn 4+ ( A = NH 4 , K, Na, Rb, Cs; X = Si, Ge, Sn, Ti, Zr) to A 3 B F 6 : Mn 4+ ( A = K, Na, Rb, Cs; B = Al, Ga), A 2 A ′BF 6 : Mn 4+ ( A = K, Na, Rb, Cs; A ′ = Li, Na, K; B = Al, Ga), A 2 C F 7 : Mn 4+ ( A = K, Na, Rb, Cs; C = Nb, Ta), and Li 3 Na 3 Al 2 F 12 : Mn 4+ …”

“…30,32,33 To date, the fluoride-based phosphors have been extended from A 2 XF 6 : Mn 4+ (A = NH 4 , K, Na, Rb, Cs; X = Si, Ge, Sn, Ti, Zr) to A 3 BF 6 : Mn 4+ (A = K, Na, Rb, Cs; B = Al, Ga), A 2 A′BF 6 : Mn 4+ (A = K, Na, Rb, Cs; A′ = Li, Na, K; B = Al, Ga), A 2 CF 7 : Mn 4+ (A = K, Na, Rb, Cs; C = Nb, Ta), and Li 3 Na 3 Al 2 F 12 : Mn 4+ . [34][35][36][37][38][39][40][41][42] In general, highly concentrated and toxic HF is usually used during the synthesis of Mn 4+ -activated fluoride phosphors. 30,32,[42][43][44] To get rid of damages from HF, HF-free synthetic methods need to be developed.…”