Narrow-band red emitting phosphor BaTiF₆:Mn⁴⁺: preparation, characterization and application for warm white LED devices

Abstract

As a new class of non-rare-earth red phosphors for high-efficiency warm white light-emitting diodes (white LEDs), Mn ion activated fluoride compounds have been extensively investigated recently and hold the potential to supersede commercial rare earth doped nitride phosphors. Herein, a series of Mn ions doped BaTiF phosphors have been prepared via the hydrothermal route using citric acid as a surfactant. After a systematic investigation, we illustrate the effects of reaction time, nominal concentration of HF solution, and reaction temperature on the luminescence performance of the phosphor. The BaTiF:Mn phosphor generates narrow red emission, which is highly perceived by the human eyes and leads to excellent chromatic saturation of red emission spectra. Simultaneously, concentration and thermal quenching are investigated systematically, and the quenching mechanisms are elucidated in detail. Employing BaTiF:Mn as a red phosphor, we fabricate a high-performance white LED with low correlated color temperature of 3974 K, high color rendering index of 90.6 and luminous efficacy of 132.54 lm W. Based on the improvement in correlated color temperature and color rendering index, the BaTiF:Mn red phosphor supplements the deficiency of LEDs fabricated by combining blue chips and only YAG:Ce, which suggests that it is a promising commercial red phosphor in warm white LEDs.

A Reverse Strategy to Restore the Moisture‐deteriorated Luminescence Properties and Improve the Humidity Resistance of Mn4+‐doped Fluoride Phosphors

“…In recent years, Mn 4 + doped fluoride phosphors have attracted widespread attention in the fields of liquid crystal display (LCD) [1] and solid-state lighting (SSL). [2] So far, a series of Mn 4 + -doped fluoride red-emitting phosphors, such as A 2 XF 6 : Mn 4 + (A = NH 4 , Li, Na, K, Rb and Cs; X = Si, Ti, Ge, Sn, Zr and Hf), [3][4][5][6] BXF 6 (6H 2 O) : Mn 4 + (B = Ba and Zn), [7][8][9][10] A 3 MF 6 : Mn 4 + (M = Al, Ga and Sc), [1,[11][12][13] A 2 NF 7 : Mn 4 + (N = Ta and Nb), [14,15] A 2 NO x F 6-x : Mn 4 + (x = 1, N = Ta and Nb; x = 2, N = W and Mo) [16][17][18][19] and A 3 XF 7 : Mn 4 + [20] has been reported. Unfortunately, although fluoride phosphors with a narrow emission at around 630 nm exhibit unique luminescence performance under blue light excitation, the deterioration of luminescent properties as a result of obvious hydrolysis has limited their large-scale application.…”

Tuning Coordination Environments of Dopants through Topochemical Reaction Enables Substantial Enhancement of Luminescence in Mn4+-Doped Perovskite

“…34 Previous work has revealed that Mn 4+ emits red light in the octahedral coordination geometry. 17 ions in Sr 3 (W,Mn)O 6 . The optimal Mn 4+ dopant content was found to be x = 0.005.…”

“…Mn 2+ can show different PL bands in the range of 450–610 nm, , while Mn 3+ , Mn 5+ , and Mn 6+ ions show near-infrared emissions, and the Mn 7+ emission has not been detected so far . Previous work has revealed that Mn 4+ emits red light in the octahedral coordination geometry . We thus assign the red light emission to the 2 E g → 4 A 2g transition of octahedrally coordinated Mn 4+ ions in Sr 3 (W,Mn)­O 6 .…”

“…Recently, Mn 4+ -doped fluoride phosphors have attracted considerable attention owing to their application as promising red phosphors in high color rendering index white-light-emitting didoes. Mn 4+ -doped phosphors feature a broad band excitation scheme and sharp emission bands associated with the 3d 3 electronic configuration of Mn 4+ . − However, Mn 4+ -doped fluoride phosphors were mainly synthesized by wet chemical routes that involve the use of hydrofluoric acid (HF), which, to a great extent, not only limits the synthesis scalability but also brings cost and safety problems. Green synthetic routes without HF were proposed to solve such problems.…”

Controlling the Morphology and Size of GdF3:RE3+ (RE = Dy, Tb, and Sm) by pH Value: Growth Mechanism, Energy Transfer, and Luminescent Properties

“…In recent years, there has been great interest in studying and developing rare earth (RE) luminescence materials on account of their potential applications, such as liquid lasers, photoelectric devices, nanolabels, multimodality bioimaging contrast agents, television tubes, mobile telephone screens, fluorescent lamps, and the promising white light-emitting diodes. − Among all kinds of RE luminescence materials, RE fluoride (such as GdF 3 ) luminescence materials have many excellent properties, for instance, long lifetime, lower energy consumption, high luminous efficiency, and environmentally friendliness, and so on. − Therefore, GdF 3 is considered to be a prominent luminescent host material.…”