Direct synthesis of Sr3Al2(OH)12 from solution for preparation of fine-grained Sr3Al2O6 phosphors at low temperature

• Sr3Al2(OH)12 can be directly deposited from solution.
• Sr3Al2O6 can be synthesized from Sr3Al2(OH)12 at the temperature as low as 600 °C.
• Luminescent center integrated into the lattices of Sr3Al2O6 at low temperature.
• The phosphors with fine grain size and the strong luminescent intensities.
• A new excitation band at 230 nm has been observed.

The precursors Sr3Al2(OH)12 can be directly precipitated from solution near room temperature under the normal pressure. The cubic Sr3Al2O6 with fine grain size can be synthesized from Sr3Al2(OH)12 at the temperature as low as 600 °C. Especially, the rare earth element, such as Eu3+ etc., as luminescent center, has been simultaneously integrated into the lattices of Sr3Al2O6. The luminescent intensities of the samples annealed at a temperature over 800 °C are strong enough for phosphors, and increase with the annealing temperatures, reach a maximum at 1200 °C and then drop down at 1300 °C. The grain sizes of all the samples annealed below 1200 °C are smaller than 1 μm and suitable for mixing with other phosphors in the applications. The photoluminescent spectra of the Sr3Al2O6:Eu3+ reveal that the intensities of both emission and excitation peaks increase with the dose of Eu3+, and reach maxima at the dose level about 1.2%, then decrease due to concentration quenching. A new excitation band at 230 nm has been observed in heavier doped samples due to the complex point defects produced by association.

A novel strategy to prepare a stable hydroxide Sr3Al2(OH)12 is developed. The strontium aluminates phosphors Eu3+ doped Sr3Al2O6 phosphors with controlled composition can been obtained at a low temperature by using Sr3Al2(OH)12 as a precursor.Figure optionsDownload as PowerPoint slide