Additives and solvents-induced phase and morphology modification of NaYF4 for improving up-conversion emission

• The effect of additives and solvents on the synthesis of NaYF4 was studied in detail.
• Ethanol can facilitate the formation of H-NaYF4 while acetic acid restrain it.
• Three general principles for improving up-conversion emission were summarized.

Both cubic and hexagonal NaYF4 were synthesized in different reaction systems via hydro/solvo-thermal route. The effects of reaction temperature, solvents, and additives on the synthesis of NaYF4 have been studied in detail. It has been shown that phase transformation from cubic NaYF4 to hexagonal NaYF4 always occurred. The sequence of the ability for inducing the phase transformation was ethanol>H2O>acetic acid. It is found that ethanol can not only facilitate the formation of hexagonal NaYF4 but also control the growth of the crystal. This is quite unusual for the growth of H-NaYF4. The up-conversion emission properties of Yb/Er co-doped NaYF4 have also been investigated and the results demonstrated some general principles for improving up-conversion emission.

Additives and solvents can induce the phase transformation of NaYF4, typically the use of organic sodium salt and ethanol.Figure optionsDownload as PowerPoint slide