New method of beta-NaYF4: Yb3+, Er3+ synthesis by using beta-cyclodextrin

• Beta-NaYF4: Yb3+, Er3+ was prepared by new method using beta-cyclodextrin.
• Beta-cyclodextrin prevents the pyrohydrolysis and allows to obtain pure samples.
• Samples prepared using beta-cyclodextrin had homogeneous distribution of elements.

The novel method of synthesis of the hexagonal modification beta-NaYF4 doped with Yb3+ (17 at.%) and Er3+ (3 at.%) using beta-cyclodextrin is proposed. Complex fluorides were prepared by decomposition of the mixture of metal fluoroacetates hydrates with and without addition of beta-cyclodextrin and were investigated by X-ray diffraction, energy dispersive X-ray analysis, scanning and transmission electron microscopy. The samples prepared by adding beta-cyclodextrin in the reaction mixture are single phase and have a hexagonal structure. At the same time, decomposition of the mixture of metal trifluoroacetates hydrates without beta-cyclodextrin is accompanied by pyrohydrolysis, leading to a contamination of the products by impurities of yttrium oxyfluorides and sodium fluoride. So a new synthetic approach proposed in this work allows to obtain pure complex fluorides with homogeneous distribution of elements and with homogeneous pore distribution.

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