Luminescence properties of Tb3+/Eu3+ co-doped glass based on GSBR system

Colour-tunable features in thermally stable Tb3+/Eu3+ co-doped telluro tungstate glasses for photonic applications

“…Dieke's energy level scheme can be utilized to predict the probability of ET across two rare-earth (RE 3+ ) ions. The ET occurs from a higher energy level of one RE 3+ ion to the lower energy level of another RE 3+ ion [33,37,38]. In the case of Tb 3+ and Eu 3+ ions, the transition levels of Tb 3+ are higher in the present investigation than that of Eu 3+ , suggesting the probability of ET may take place from Tb 3+ to Eu 3+ ions.…”

“…Hence, it is probable that the energy from Tb 3+ ions was partially transferred non-radiatively to Eu 3+ ions leading to a decrease in the emission of Tb 3+ ions. The energy gap between the 5 D 4 level and 5 D 0 level is smaller than that making the ET possible through phonon-assisted NRT [22,38]. This suggests that the Tb 3+ ion is an efficient sensitizer for the Eu 3+ ions.…”

“…In the case of Tb 3+ and Eu 3+ ions, the transition levels of Tb 3+ are higher in the present investigation than that of Eu 3+ , suggesting the probability of ET may take place from Tb 3+ to Eu 3+ ions. The spectrum overlap between the donor (Tb 3+ ) emission and acceptor (Eu 3+ ) excitation is one of the most crucial conditions for ET [38]. The excitation peak around 534 nm corresponds to the 7 F 1 → 5 D 1 electronic transition of Eu 3+ ions overlapping with the emission peak around 545 nm is attributed to the 5 D 4 → 7 F 5 transition of Tb 3+ ions as depicted in figure 7.…”

“…Figure 13 illustrates that the PL lifetime measurement has been measured via fixed green emission (545 nm) wavelength excited by 378 nm excitation wavelength to explore the lifetime of Tb 3+ activated and Tb 3+ /Eu 3+ co-activated TWKZBi glasses. The lifetime profiles have been most exceptionally fitted with the bi-exponential equation as presented in the literature [38,41]. The average lifetime (τ Avg ) for Tb 3+ /Eu 3+ co-doped TWKZBi glasses have been calculated via applying the following relation [41]: where, the PL intensities of the TWKZBiTbEu glasses at time 0 and t seconds are represented as I 0 and I (t).…”