Energy Transfer between Tb3+ and Eu3+ in LaPO4: Pulsed versus Switched‐off Continuous Wave Excitation

Abstract

Abstract The energy transfer (ET) between Tb3+ and Eu3+ is investigated experimentally and with available theoretical models in the regime of high Tb3+ concentrations in ≈30 nm LaPO4 nanoparticles at room temperature. The ET efficiency approaches 100% even for lightly Eu3+‐doped materials. The major conclusion from the use of pulsed laser excitation and switched‐off continuous wave laser diode excitation is that the energy migration between Tb3+ ions, situated on La3+ sites with ≈4 Å separation, is not fast. The quenching of Tb3+ emission in singly doped LaPO4 only reduces the luminescence lifetime by ≈50% in heavily doped samples. Various theoretical models are applied to simulate the luminescence decays of Tb3+ and Tb3+, Eu3+‐doped LaPO4 samples of various concentrations and the transfer mechanism is identified as forced electric dipole at each ion.

Keywords

• energy transfer
• lanthanide
• migration
• pulse and continuous wave excitation