Synthesis and luminescence properties of Tb³⁺/Eu³⁺ co-doped GdAlO₃ phosphors with enhanced red emission

Qi Chen，Jinkai Li，Wenzhi Wang

School of Materials Science and Engineering,University of Jinan

摘 要：The(Gd_0.97-xEu_xTb_0.03)AIO₃（x= 0.005-0.07） phosphors were synthesized by the co-precipitation method,using ammonium bicarbonate as a precipitant.The combined technologies of FT-IR,XRD,FESEM,PLE/PL and photo luminescence decay analysis were used to study the phase evolution,morphologies and luminescent properties.The phosphors with good dispersion exhibit strong vivid red emission located at 617 nm(⁵ D₀-⁷ F₂ transition of Eu³⁺) under the optimal excitation wavelength of 275 nm(⁴ f⁸-4 f⁷5 d¹ transition of Tb³⁺,⁸ S_7/2→6^I_J transition of Gd³⁺).The presence of Gd³⁺ and Tb³⁺ excitation bands on the PLE spectra monitoring the Eu³⁺ emission directly gives an evidence of Tb³⁺ → Eu³⁺ and Gd³⁺ → Eu³⁺ energy transfer,The emission intensity varies with the Eu³⁺ amount,and the quenching concentration is ～5 at% which is close to the calculated value.The quenching mechanism is determined to be the exchange reaction between Eu³⁺.The temperature-dependent PL analysis indicates that the best(Gd_0.92Eu_0.05Tb_0.03)AlO₃ sample possesses good thermally stable properties.All the(Gd_0.97-xEu_xTb_0.03)AIO₃ phosphors in this work have similar CIE chromaticity coordinates and color temperatures,which are（0.65 ± 0.02,0.35 ± 0.02） and ～2558 K,respectively.Fluorescence decay analysis shows that the lifetime for～617 nm emission decreases with the content of Eu³⁺ and temperature increasing.Owing to the Tb³⁺→ Eu³⁺ energy transfer,the luminescent properties of the(Gd_0.92Eu_0.05Tb_0.03)AlO₃ phosphors are superior to the single Eu³⁺ doped sample(Gd_0.95Eu_0.05)AlO₃.As a result,the prepared phosphors may be widely used in solid-state display and light emitting devices.

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