Mn⁴⁺doped (NH₄)₂TiF₆and (NH₄)₂SiF₆micro-crystal phosphors: synthesis through ion exchange at room temperature and their photoluminescence properties

Abstract

Two red micro-crystal phosphors: (NH4)2TiF6:Mn4+and (NH4)2SiF6:Mn4+have been obtained through ion exchange at room temperature for a few hours. The reaction mechanism and luminescence properties of them have been comprehensively invested.

Formation mechanism and optimized luminescence of Mn4+‐doped unequal dual‐alkaline hexafluorosilicate Li0.5Na1.5SiF6

“…The excitation and emission spectra, and the decay curves of the red phosphor LNSF:Mn measured at 78 and 298 K are shown in Figure . The two excitation bands peaking at 370 and 470 nm in the excitation spectra monitored at 620 nm are due to the 4 A 2g → 4 T 1g and 4 A 2g → 4 T 2g transitions of Mn 4+ according to the Tanabe‐Sugano diagram for Mn 4+ , which are consistent with the reported results of other Mn 4+ activated fluoride compounds . The maximum excitation band locating in blue region indicates that the red phosphor LNSF:Mn shows great promise in GaN based WLEDs.…”

“…S5 exhibits that the FTIR spectra of the red phosphor samples LNSF:Mn and NSF:Mn are very similar because the FTIR absorption of the both crystals are primarily ascribed to the vibrations of the Si-F bond. The main peaks at 722 and 451 cm À1 are likely due to the vibrations of the Si-F bonds in [SiF 6 ] 2À groups 46,47. The diffuse reflection spectra (DRS) of undoped LNSF, phosphors LNSF:Mn and NSF:Mn are depicted inFigure S6.…”

Surface Passivation toward Highly Stable Mn4+‐Activated Red‐Emitting Fluoride Phosphors and Enhanced Photostability for White LEDs

“…For this issue, red‐emitting phosphors have been extensively investigated to improve CRI of WLEDs . Most recently, the Mn 4+ ‐activated narrow‐band red‐emitting fluorides phosphors, such as A 2 XF 6 :Mn 4+ (A = Li, Na, K, Rb, and Cs; A 2 = Ba, Zn; X = Si, Ge, Sn, Ti, Zr, and Hf), A 3 MF 6 :Mn 4+ (M = Al, Ga, Sc), and A 2 NF 7 :Mn 4+ (N = Nb, Ta), have gained increasing attention because of their broadband absorption in the blue region, good thermal stability, and suitable spectral profile in the red region . Moreover, the narrow‐band red component can improve the luminous efficiency of the final WLEDs device except for the contribution in the enhanced CRI.…”

Synthesis and photoluminescence characteristics of high color purity Ba3Y4O9:Eu3+red-emitting phosphors with excellent thermal stability for warm W-LED application

“…During the past decades, frequency conversion using luminescent materials, which can convert incident radiation into desired wavelengths, has been widely applied in various elds, such as lighting, displays, bioimaging, sensors, and solar cells. [1][2][3][4][5][6] In recent years, white light-emitting diodes (W-LEDs) have gradually replaced traditional incandescent and uorescent lamps owing to their obvious advantages, such as high efficiency, low energy cost, environmental friendliness, and long lifetime. [7][8][9][10][11][12][13][14][15] They are widely applied in residential lighting, automotive lighting, displays, and so on.…”