Radiative transitions of Eu³⁺ in non-crystalline alkali- alkaline- titanate film

Non-crystalline Eu³⁺-doped alkali-alkaline-titanate films have been fabricated by sol-gel route under low-temperature heating, and bright red emissions have been observed under UV radiation. Refractive index and thickness of the films calculated from the transmittance spectrum are 1.481 and 377 nm, respectively. Based on Judd-Ofelt theory, the optical intensity parameters Ω₂ and Ω₄ derived from the emission spectrum were 6.92 × 10^-20 and 1.84 × 10^-20 cm ², respectively. The calculated radiative lifetime of ⁵D₀ level (3.67ms) was estimated to be much longer than those in phosphate and fluorophosphates glasses, which is beneficial for achieving visible laser radiations. The homogeneous amorphous films with intense red emissions are promising candidates to develop illuminant, display, light conversion and optical waveguide devices.