Tunable blue–green emission properties of Tb3+ doped barium tantalate phosphor

Structural and tunable optical properties of LiMgPO4:Tb3+ phosphor fabricated by sol–gel method

“…Initially, the reduction in luminescence centers at lower Tb 3+ concentrations results in a decrease in the relative emission intensity. However, the relative emission intensity of the 5 D 3 transition increases at lower Tb 3+ doping levels due to the decrease of the cross‐relaxation effect that inhibits the 5 D 3 state 14–16 . As a result, the emission intensity of the 5 D 3 state does not exhibit a consistent pattern, unlike the 5 D 4 state, because these two effects act in opposing directions.…”

“…Nevertheless, the PL emission intensity ratio of the 5 D 3 → 7 F 5 and 5 D 4 → 7 F 5 transitions shows an exponential correlation, which depends on the concentration of Tb 3+ , as shown in Figure 9. The decrease in emission intensity from 5 D 3 → 7 F J and the increase in emission intensity from 5 D 4 → 7 F J are dependent on the concentration of Tb 3+ and can be explained by Equation () through cross‐relaxation, 14–16 and this process are given in Figure 10, where there is a transition from processes (1) to (2) with increasing Tb 3+ concentration: $$$$\begin{equation}{\mathrm{T}}{{\mathrm{b}}^{{\mathrm{3 + }}}}\left[ {^{\mathrm{5}}{{\mathrm{D}}_{\mathrm{3}}}} \right]{\mathrm{ + T}}{{\mathrm{b}}^{{\mathrm{3 + }}}}\left[ {^{\mathrm{7}}{{\mathrm{F}}_{\mathrm{6}}}} \right] \to {\mathrm{T}}{{\mathrm{b}}^{{\mathrm{3 + }}}}\left[ {^{\mathrm{5}}{{\mathrm{D}}_{\mathrm{4}}}} \right]{\mathrm{ + T}}{{\mathrm{b}}^{{\mathrm{3 + }}}}\left[ {^{\mathrm{7}}{{\mathrm{F}}_{\mathrm{0}}}} \right]\end{equation}$$$$…”

“…These materials have found versatile applications in various fields, including electroluminescent and screen technology, lasers, W‐LEDs, biomedical diagnosis applications, fluorescent technology, laser spectroscopy, optical storage systems, and optical fiber amplifiers, which show rapid and remarkable progress in this area 1–13 . Typically, when incorporated into various host matrices, the trivalent terbium (Tb 3+ ) ion exhibits green emission when excited by different radiation sources like ultraviolet (UV) and X‐rays 14–18 . The green emissions in Tb 3+ ‐doped phosphors originate from transitions between the 5 D 4 and 7 F J states (J = 0–6).…”

“…The green emissions in Tb 3+ ‐doped phosphors originate from transitions between the 5 D 4 and 7 F J states (J = 0–6). Additionally, blue emissions from the 5 D 3 state can be monitored, which are influenced by the phonon spectrum of the host structure and the concentration of Tb 3+ doping 14–16 . The occurrence of low phonon frequency and minimal amounts of Tb 3+ in the host structure will inhibit multiphonon relaxation and cross‐relaxation among Tb 3+ ions, leading to noticeable blue emissions from Tb 3+ .…”

“…The occurrence of low phonon frequency and minimal amounts of Tb 3+ in the host structure will inhibit multiphonon relaxation and cross‐relaxation among Tb 3+ ions, leading to noticeable blue emissions from Tb 3+ . As a result, selecting an appropriate host structure and optimal Tb 3+ concentrations allows the production of different emission colors in Tb 3+ ‐doped phosphors 14–25 …”