Influence of Mn2+ ions on the structure and spectral properties of BaY2F8: Yb3+/Ho3+ phosphors

Utilizing Energy Transfer in Mn2+/Ho3+/Yb3+ Tri-doped ZnAl2O4 Nanophosphors for Tunable Luminescence and Highly Sensitive Visual Cryogenic Thermometry

“…The changes in the photophysical dynamics of UC can be attributed to the energy transfer (ET) between Mn 2+ and Ho 3+ ions. 31 − 34 The codoping of Mn 2+ ions induces ET pathways, and thus, the red-to-green UCL ratio (R/G) value increased from 5.2 in the 1%Ho 3+ + 5%Yb 3+ -doped sample to 17.3 in the 2 mol % Mn 2+ -codoped sample ( Figure 3 d), highlighting its potential for singular red unconvertible materials. We could successfully achieve 94% red emission in the 2 mol % Mn 2+ -codoped samples in comparison to 84% red emission obtained in the sample without Mn 2+ ions ( Table S4 ).…”

“…As a result of the changes in the relative radiative probabilities of transitions ascribed to (542, 550), 669, and 652 nm UC emissions, the color tunability from yellow to green to red with increasing concentrations of Mn 2+ ions could be achieved as can be also schematically visualized in Figure a. The changes in the photophysical dynamics of UC can be attributed to the energy transfer (ET) between Mn 2+ and Ho 3+ ions. − The codoping of Mn 2+ ions induces ET pathways, and thus, the red-to-green UCL ratio (R/G) value increased from 5.2 in the 1%Ho 3+ + 5%Yb 3+ -doped sample to 17.3 in the 2 mol % Mn 2+ -codoped sample (Figure d), highlighting its potential for singular red unconvertible materials. We could successfully achieve 94% red emission in the 2 mol % Mn 2+ -codoped samples in comparison to 84% red emission obtained in the sample without Mn 2+ ions (Table S4).…”

“…The ET probability between Ho 3+ and Mn 2+ ions is high, and this can be attributed to energy matching that leads to effective mixing of their wave functions. As both the Ho 3+ and Mn 2+ ions are present in close proximity, the possibility of back energy transfer (BET) processes is also higher and BET may occur from the 4 T 1 energy level of Mn 2+ ions to the Ho 3+ ions by nonradiative relaxation to the ground state. , Interestingly, either the red and green UC emission intensities or one of them could be modulated depending on the host matrices and energy transfer pathways. ,,, The BET from the 4 T 1 energy state of Mn 2+ ions can occur to either of the ( 5 F 4 , 5 S 2 ) or 5 F 5 excited levels of Ho 3+ ions that could selectively enhance one of the radiative transitions of Ho 3+ ions. The increase in the R/G value strongly supports the possible efficient ET between Ho 3+ and Mn 2+ ions.…”

“…Therefore, the entire focus is on exploring the manganese ion for generating singular red emission in upconvertible phosphors. In recent years, there are many publications exploring the ET between Er 3+ and Mn 2+ ions that are useful for attaining color tunability by manipulation of the red-to-green (R/G) ratio. − However, achieving a single-component red UC emission in Ho 3+ –Yb 3+ -based hosts has been very challenging, and there are few reports on the effect of codoping Mn 2+ in Ho 3+ /Yb 3+ -based UC phosphors. − To be noteworthy, most of the reports have considered the fluoride-based host lattice for studying the Ho 3+ and Mn 3+ ET processes in the Yb 3+ /Ho 3+ /Mn 2+ system that may raise safety concerns over long-term biomedical applications . Particularly, the literature for investigating the effect of Mn 2+ codoping in Ho 3+ /Yb 3+ -based oxide host matrices is very limited.…”

“… 22 − 30 However, achieving a single-component red UC emission in Ho 3+ –Yb 3+ -based hosts has been very challenging, and there are few reports on the effect of codoping Mn 2+ in Ho 3+ /Yb 3+ -based UC phosphors. 31 − 34 To be noteworthy, most of the reports have considered the fluoride-based host lattice for studying the Ho 3+ and Mn 3+ ET processes in the Yb 3+ /Ho 3+ /Mn 2+ system that may raise safety concerns over long-term biomedical applications. 6 Particularly, the literature for investigating the effect of Mn 2+ codoping in Ho 3+ /Yb 3+ -based oxide host matrices is very limited.…”