Photoluminescence of BaZrSi3O9:Bi3+ as a yellow emitting phosphor for White LEDs

• BaZrSi3O9:Bi3+ has a broad absorption band in 300–400 nm and gives bright yellow emission.
• BaZrSi3O9:Bi3+ exhibits a good thermal stability with increasing heating temperature.
• BaZrSi3O9:Bi3+ shows excitation-dependent emission.

A yellow-emitting phosphor, BaZrSi3O9:Bi3+, was synthesized in air via solid state reaction method. Luminescence properties of this phosphor were examined by steady-state and time-resolved as well as temperature-dependent luminescence spectra. The obtained BaZrSi3O9:Bi3+ sample shows strong absorption in 300–400 nm, and gives bright and broad yellow emission centered at 560 nm upon 350 nm excitation. The broad emission is originated from 3P1 → 1S0 transition of Bi3+, which has a lifetime around ∼1 μs in BaZrSi3O9. Upon heating in the temperature range from room temperature to 250 °C, accompanied by the emission intensity deceases (emission intensity at 150 °C retains 76% its initial intensity at room temperature), the emission of Bi3+ in BaZrSi3O9 is blue-shifted, which is ascribed to the thermally active phonon-assisted tunneling from the lower energy to the higher energy emission band in the excited states of Bi3+.

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