Reconstruction of Mn4+-free shell achieving highly stable red-emitting fluoride phosphors for light-emitting diodes

Towards improved waterproofness of Mn4+-activated fluoride phosphors

“…In 2021, Wan et al 29 reported a reduction-assisted surface recrystallization (RSRC) strategy to construct a Mn 4+ -free shell for K 2 SiF 6 :Mn 4+ . To construct this Mn-free shell, when the Mn 4+doped fluoride formed a saturated solution in HF reaching a dissolution-crystallization equilibrium, a reducing agent was added in the solution to remove the Mn 4+ ions, thus preventing Mn 4+ from recrystallization.…”

“…9 Structural formula of four α-hydroxy acids (1) tartaric acid, (2) lactic acid, (3) malic acid, (4) citric acid, and the possible redox reaction between the tartaric acid and Mn 4+ ion. 29 The strategy of constructing a deactivated layer with surface reduction of Mn 4+ can evidently improve the waterproofness of fluoride phosphors. The reported reducing agents include both organic and inorganic ones with varying reducing power.…”

Color‐Tunable Single‐Phase Bi3+/Eu3+‐Activated LiCa3ZnV3O12 Luminescence Materials Based on Energy Transfer

“…A solid state lighting using light emitting diodes (LEDs) as new light sources are known as the most promising new generation of green lighting sources for their advantages of high electro‐optical conversion efficiency, long life, energy conservation and environmental protection, fast response, and small size. At the same time, it is also identified as the fourth‐generation lighting source that would inevitably displace the high energy consumption incandescent lamps, mercury‐polluted fluorescent lamps and high‐pressure sodium lamps [1,2] . At present, the most widely used and most effective W‐LEDs in the market, its mainstream solution is “phosphor‐conversion technology”, that is, coating the surface of the LED chips with phosphors.…”

“…Therefore, phosphors are the important factors affecting the performance of W‐LEDs devices. Phosphor materials with excellent physical and chemical properties are ideal luminescence materials for W‐LEDs [2–4] . In order to meet the needs of indoor lighting, it is essential to find phosphors with suitable spectral distribution to match LED chips : that is, to develop phosphors with adjustable optical properties [5–7] …”

“…Phosphor materials with excellent physical and chemical properties are ideal lumines-cence materials for W-LEDs. [2][3][4] In order to meet the needs of indoor lighting, it is essential to find phosphors with suitable spectral distribution to match LED chips : that is, to develop phosphors with adjustable optical properties. [5][6][7] As far as we know, phosphors that realize multi-color emission mainly use rare earth ions as luminescent centers (such as Ce 3 + and Eu 2 + ), [8,9] but the imbalance between supply and demand of rare earth ions and their high price limit their wide application.…”