Enhancing Structural Rigidity via a Strategy Involving Protons for Creating Water-Resistant Mn⁴⁺-Doped Fluoride Phosphors

Abstract

The poor water resistance property of a commercial Mn 4+ -activated narrow-band red-emitting fluoride phosphor restricts its promising applications in high-performance white LEDs and wide-gamut displays. Herein, we develop a structural rigidity-enhancing strategy using a novel KHF 2 :Mn 4+ precursor as a Mn source to construct a proton-containing water-resistant phosphor K 2 (H)TiF 6 :Mn 4+ (KHTFM). The parasitic [HMnF 6 ] − complexes in the interstitial site from the fall off the KHF 2 :Mn 4+ are also transferred to the K 2 TiF 6 host by ion exchange to form KHTFM with rigid bonding networks, improving the water resistance and thermostability of the sample. The KHTFM sample retains at least 92% of the original emission value after 180 min of water immersion, while the non-water-resistant K 2 TiF 6 :Mn 4+ (KTFM) phosphor maintains only 23%. Therefore, these findings not only illustrate the effect of protons on fluoride but also provide a novel insight into commercial water-resistant fluoride phosphors.

Spectral Red Shift of Cs4Mn(Bi1–xInx)2Cl12 Layered Double Perovskite by Adjusting the Microstructure of the [MnCl6]4– Octahedron

“…This distortion mainly results from the asymmetric stretching of the [MnCl 6 ] 4– octahedron. Therefore, the polyhedral distortion index (D) can be calculated using the following equation , where d i is the distance from the central atom to the i th coordinating atom and d av is the average length of all bonds. The result clearly shows that the polyhedral distortion index increases linearly with the increase in the In 3+ ion doping content, as shown in Figure b.…”

An organic–inorganic hybrid K2TiF6 : Mn4+ red-emitting phosphor with remarkable improvement of emission and luminescent thermal stability

“…They are attributed to the spin-forbidden d-d transition ( 2 E g / 4 A 2g ) of Mn 4+ , and are activated by the [MnF 6 ] 2À vibration mode. [19][20][21][22] Fig. 3(c) depicts the lifetime curves of KTF : Mn 4+ and KTF : MEAH + , Mn 4+ .…”

Novel Cyan-Green-Emitting Bi3+-Doped BaScO2F, R+ (R = Na, K, Rb) Perovskite Used for Achieving Full-Visible-Spectrum LED Lighting

“…Usual phosphor hosts include silicates, vanadates, garnets, fluorides, phosphates, and so on. − Of these, perovskites are also typical phosphor hosts because of the simple synthesis conditions and stable properties. The typical perovskite structure matrix ABO 3 by anion (F – ) substitution, for example, BaScO 2 F with the A 2+ B 3+ [X 2– ] 2 [Y – ] stoichiometry, is used as a matrix for photoluminescence materials.…”