Transparent glass ceramics activated with rare earth ions are valued for their excellent optical properties [1]. Silica–hafnia binary systems have emerged as an ideal matrix for integrating rare earth ions into hafnia nanocrystals, resulting in a considerable increase in luminescence and allowing for a wide variety of important applications. This work focuses on the Tb³⁺/Yb³⁺-driven down-conversion process, widely utilized in photovoltaic systems.

Following a well-consolidated protocol and an appropriate thermal treatment, the silica–hafnia glass-ceramic films were fabricated using the spin-coating technique via the sol–gel method. Interestingly, sol–gel technology offers the ability to create multicomponent materials with controlled composition, shape, morphology, and optical properties for the final product.

This investigation concentrates on silica–hafnia glass-ceramic films with a composition of 70SiO₂-30HfO₂ that have been doped with 19% rare earth ions ([Tb + Yb] / [Si + Hf] = 19%). Two primary findings are examined: (a) the temperature dependence of the intensity and broadening of the Yb³⁺ emission band at 975 nm and (b) the Tb³⁺ → Yb³⁺ energy transfer mechanism, which is based on proposed mechanisms from the existing literature. Furthermore, the power dependence of Yb³⁺ luminescence (²F_5/2 → ²F_7/2) is examined in relation to this subject [2].

In summary, these results underline the suitability of SiO₂-HfO₂ glass ceramics for photonic applications and enhance our understanding of the Tb³⁺ → Yb³⁺ down-conversion dynamics in this system.

References

[1] M.Ferrari, G.C. Righini, International Journal of Applied Glass Science, 6,240-248 (2015)

[2] Salima El Amrani, Michael Sun, Sirona Valdueza-Felip, Fernando B. Naranjo, Mohammed Reda Britel, Maurizio Ferrari, Adel Bouajaj, Effect of temperature and excitation power on down-conversion process in Tb3+/Yb3+-activated silica-hafnia glass-ceramic films,Ceramics International,2024,ISSN 0272-8842 .https://doi.org/10.1016/j.ceramint.2024.06.392.