Novel far-red-emitting SrGdAlO₄:Mn⁴⁺ phosphors with excellent responsiveness to phytochrome P_FR for plant growth lighting

Abstract

In this paper, we reported on novel Mn4+-activated SrGdAlO4 far-red-emitting phosphors with excellent responsiveness to phytochrome PFR for potential application in plant growth lighting.

Synthesis, characterization, and thermoluminescence‐based high‐dose neutron and gamma dosimetry study of Al5BO9: Mn, Li nanophosphor

“…The emission at 615 nm may be correlated to the Mn 2+ ion situated at octahedral Al‐site 47,48 . Moreover, the emission band around 680 nm is closely matching with that of Mn 4+ ion as reported earlier 49,50 . Therefore, the present compound might be containing the mixture of Mn 2+ and Mn 4+ ions.…”

“…Moreover, the other peaks situated at 364 and 452 nm also correspond to the Mn 4+ ‐related excitation 51 . The sharp emission band within 675–750 nm (with FWHM ∼41 nm) was observed due to the 2 E g → 4 A 2g transitions of Mn 4+ ion 50,52 . This clearly indicated the conversion of Mn 2+ to Mn 4+ at higher temperature–annealed compound 51,53 .…”

“…Further, one of the compounds (Al 5 BO 9 : 0.001Mn, 0.01Li) was heated at 1423 K for 2 h, and the corresponding PL excitation and emission spectra are shown in Figure 10. The excitation spectra showed two well‐resolved peaks situated at 310 and 490 nm, which might be attributed to the Mn–O charge‐transfer transition, and the Mn 4+ spin allowed transition 4 A 2g → 4 T 2g , respectively 49,50 . Moreover, the other peaks situated at 364 and 452 nm also correspond to the Mn 4+ ‐related excitation 51 .…”

“…47,48 Moreover, the emission band around 680 nm is closely matching with that of Mn 4+ ion as reported earlier. 49,50 Therefore, the present compound might be containing the mixture of Mn 2+ and Mn 4+ ions. The CIE color coordinate diagrams of various Mn-doped samples were calculated, as shown in Figure 9.…”

Deep‐red‐emitting Ca2ScSbO6:Mn4+ phosphors with a double perovskite structure: Synthesis, characterization and potential in plant growth lighting

“…The decrease of peak intensity with temperature rising is shown in the inset of Figure 8A, which is due to the thermal quenching effect. Particularly, it was found that the emission intensity at 423 K (commercial LEDs operating temperature) maintained 61.4% of that at room temperature 303 K, demonstrating a better thermal-quench resistance compared with some previously reported Mn 4+ -doped phosphors, such as SrLaMgSbO 6 :Mn 4+ (I 423K /I 303K ≈ 20%), 41 Sr 2 LuTaO 6 :Mn 4+ (I 423K /I 303K ≈ 25%), 42 BaLaMgNbO 6 :Mn 4+ (I 423K /I 303K ≈ 15%), 43 SrGdAlO 4 :Mn 4+ (I 423K /I 303K ≈ 20%), 44 et al To further understand the thermal quenching mechanism of the CSS:Mn 4+ phosphor, the activation energy ΔE was calculated according to Arrhenius's equation 45 :…”