As an alternative WLED red phosphor, BaTiO3 sol-gel based ultra-thin films were doped with various mol% of Eu3+ and annealed at 500 °C. The films were amorphous with short range ordered structure as seen via XRD and Raman analysis. Photoluminescence (PL) emission spectra enabled the determination of Eu3+ location asymmetry in the host via Judd-Ofelt (J-O) theory, from which Ω2=9.37×10−20cm2 and Ω4=1.55×10−20cm2 were derived, proving that the Eu3+ ions were non-centrosymmetrically located. This enhanced the Eu3+ 5D0 → 7F2 electric-dipole transition at 614.0 nm with the strongest emission from 30 mol% doping. 395 nm excited intense and narrow red spectral profiles which exhibited excellent colour coordinates (x = 0.657, y = 0.342), quantum efficiency (25.7% at a film thickness of ∼380 nm), and colour purity of (92.0%) whereby the red to orange ratio (R: O) enables colour tailoring with 5 mol% to 30 mol% Eu3+doping. This facilitates flexible control over the colour output, ensuring that it can be easily tailored to meet specific application requirements. The aforementioned results indicate that the red-emitting Eu3+ activated amorphous BaTiO3 ultra-thin film phosphors exhibit promising potential for application in n-UV excited WLEDs as a red phosphor with a branching ratio β0→2=81.43% making it a potential candidate for red laser materials too.
