An efficient far‐red emission Sr₂InSbO₆:Mn⁴⁺, M (M = Li⁺, Na⁺, and K⁺) phosphors for plant cultivation LEDs

Abstract

High‐efficiency and far‐red light phosphors based on Mn4+‐doped inorganic luminescence materials are beneficial to plant cultivation. However, Mn4+‐doped oxide phosphors have a common problem of low quantum efficiency. Alkali metal ion codoping can effectively improve the luminescence properties of Mn4+‐activated oxide phosphors. Herein, a series of Sr2InSbO6:Mn4+, M (SISO:Mn4+, M) (M = Li+, Na+, and K+) far‐red‐emitting phosphors codoped alkali metal ions were first synthesized. Density functional theory calculation indicated that SISO is a kind of indirect bandgap material with a bandgap of ∼1.60 eV. The SISO:Mn4+ samples showed a far‐red light at 698 nm upon 365 nm, which perfectly matched the absorption spectrum of the far‐red‐phytochrome (Pfr) of plants. The doping concentration of the SISO:Mn4+ samples was optimized to be 0.006 mol. The concentration quenching mechanism was defined as dipole–dipole interaction by combining the Dexter theory and the Inokuti–Hirayama model. Optimizing the sintering temperature and codoped with alkali metal ions (Li+, Na+, and K+) could improve the luminescent intensity of SISO:Mn4+. The optimum sintering temperature was 1300°C. The internal quantum efficiencies of SISO:0.006Mn4+ and SISO:0.006Mn4+, 0.006Li+ phosphors are 22.67% and 60.56%, respectively. SISO:Mn4+, Li+ phosphors‐based plant growth light‐emitting diodes (LEDs) demonstrate excellent optical stability and long lifetime. Thus, these phosphors are promising candidates for plant cultivation LEDs.

Thermally stable rare-earth-free double perovskite phosphors toward dual-mode optical thermometry and dual-functional lighting sources

“…According to eqn (10), the value of b 1 for the SLSO:Mn 4+ phosphors was calculated to be 0.9844 (less than 1), suggesting that the matrix is a covalent oxide conformed to the experimental matrix SLSO. 39 Furthermore, the internal QY is a significant evaluation index in the practical application of phosphors, which can be obtained by the following formula: 40…”

Luminescence enhancement of Mn4+‐activated double‐perovskite phosphors for LEDs through a co‐replacement strategy

“…Therefore, the Li + ions doped in the matrix will replace the Mg 2+ ions, and the Li + ions and Mn 4+ ions will replace the Mg 2+ ions and Al 3+ ions, respectively, to achieve charge balance. As a result, the thermal stability of the sample is further improved after the addition of Li + ions 51,52 . In addition, the addition of alkali metal Li + ions to the phosphor as a flux will improve the luminescence performance of the phosphor 52,53 .…”

“…As a result, the thermal stability of the sample is further improved after the addition of Li + ions. 51,52 In addition, the addition of alkali metal Li + ions to the phosphor as a flux will improve the luminescence performance of the phosphor. 52,53 The addition of the alkali metal Li + ions to MLAT phosphors will reduce the synthesis temperature of the phosphor and increase the crystallinity of the MLAT matrix, thus enhancing the luminescence intensity.…”

Deep-red-emitting phosphors of Mn4+-activated tantalite for high-sensitivity lifetime thermometry and security films

“…To date, tetravalent manganese (Mn 4+ ) ions-doped materials with specific 3d 3 electron structures, which were found to give a strong deep-red emission under a broad excitation band, have attracted much attention for application in various advanced fields, such as WLEDs, fingerprint detection, plant cultivation, wide-gamut displays, luminescent thermometers, and flexible anti-counterfeiting films. [14][15][16][17][18][19][20][21][22][23][24] In particular, inorganic double-perovskite materials with octahedral sites are considered to be beneficial for the splitting of the Mn 4+ crystal field to obtain candidates with excellent lumines-cent performances, such as Gd 2 MgTiO 6 :Bi 3+ /Mn 4+ , 25 Y 2 MgTiO 6 :Mn 4+ , 26 La 3 Li 3 W 2 O 12 :Eu 3+ /Mn 4+ , 27 Ba 2 CaWO 6 : Mn 4+ , 28 La 2 ZnTiO 6 :Mn 4+ , 29 and (Ca,Sr,Ba) 2 CaWO 6 :Mn 4+ phosphors. 30 Herein, the double-perovskite structures with octahedral sites cooperating with Mn 4+ are shown to be an effective strategy for developing high-performance phosphors.…”