Efficient ultra-broadband NIR-II emission achieved by multi-site occupancy in Mg3Ga2GeO8: Ni2+ phosphor

Deep red emission from rare-earth-free calcium aluminozincate phosphor with the substitution of Cr3+ ion

“…The efficiency of the synthesized material was shown to rise with an increase in doping up to 0.03 mol, after which it continues to decrease as the luminescence deteriorates at higher concentration due to the quenching mechanism. The EQY ( η ) of the Ca 3− x Al 4 ZnO 10 : x Cr 3+ (where x = 0.03 mol) phosphor is calculated as 46.80% under the excitation of 540 nm, which is significantly higher in comparison to previously published studies, such as the KSrVO 4 (EQY: 41.64%), 38 Ba 2 SrWO 6 :Mn 4+ (EQY: 39.55), 39 Mg 3 Ga 2 GeO 8 :Ni 2+ (EQY: 7.3%) 40 phosphor. This relatively higher quantum yield value signifies the practical application of the phosphor under study.…”

Synergistic enhancement of the near-infrared luminescence properties of Ni2+-doped SrTiO3 perovskite phosphors and their application

“…The NIR emission of Ni 2+ is accompanied by the non-radiative relaxation of electrons from the excited state of 3 T 1g (P) to 3 T 2g (F), and then from 3 T 2g (F) to the ground state 3 A 2g (F); when the temperature increases, the vibration of the electrons in the excited state 3 T 2g (F) energy level is enhanced, which means that the electrons of Ni 2+ are pumped to the intersection of 3 A 2g (F) and 3 T 2g (F), which increases the probability that the electrons directly break through the thermal quenching activation energy to non-radiative transitions. 32…”

“…The NIR emission of Ni 2+ is accompanied by the non-radiative relaxation of electrons from the excited state of 3 T 1g (P) to 3 T 2g (F), and then from 3 T 2g (F) to the ground state 3 A 2g (F); when the temperature increases, the vibration of the electrons in the excited state 3 T 2g (F) energy level is enhanced, which means that the electrons of Ni 2+ are pumped to the intersection of 3 A 2g (F) and 3 T 2g (F), which increases the probability that the electrons directly break through the thermal quenching activation energy to non-radiative transitions. 32 In order to demonstrate the performance and practical application of the optimized SrTiO 3 -Ni 2+ -Yb 3+ -Ta 5+ phosphor in NIR pc-LED devices, the SrTiO 3 -Ni 2+ -Yb 3+ -Ta 5+ phosphor (Fig. 7a top) was mixed with silicone resin, and then packaged into a commercial UV InGaN chip (@365nm) (Fig.…”

Tunable Spinel Structure Phosphors: Dynamic Change in Near‐Infrared Windows and Their Applications

“…Mg 3 Ga 2 GeO 8 :0.8%Ni 2+ (MGG:Ni 2+ ) phosphor is considered the solid solution of intermediate spinel MgGa 2 O 4 and inverse spinel Mg 2 GeO 4 that create the complex coordinated sites in the crystal structure. [ 87 ] The tunable and ultra‐broadband emission 1000–1700 nm (peak centered at 1410 nm) with FWHM up to 300 nm achieves not only because Ni 2+ is located at crystal weak crystal field but also because the multiple sites occupation constructs the overlay emission (Figure 8c). Three Ni 2+ emitting centers existing with different intensities in MGG dominate the emission peak respectively when varying the doping concentration of Ni 2+ (Figure 8d).…”

“…d) The emission spectra of MgGa 2 O 4 (MGG) doped with different percentages of Ni 2+ (x = 0.2, 0.8, 2.0) were measured under excitation at 665 nm. Adapted with permission [87]. Copyright 2023, Elsevier B.V.…”