Correlation between Size-Dependent Luminescent Properties and Local Structure around Eu³⁺ Ions in YBO₃:Eu Nanocrystals: An XAFS Study

X-ray absorption fine structure spectroscopy (XAFS), a powerful tool for the study of the local environment of a particular element, especially the luminescent center, was introduced to investigate the correlation between luminescent properties and local structure around Eu 3+ ions in YBO 3:Eu nanocrystals, which was prepared by a more facile sol−gel pyrolysis process in our previous work and which exhibited size-dependent chromaticity, that is, a relatively better chromaticity could be obtained in the smaller-sized samples. The YBO 3:Eu phosphors were studied at the Eu L III edge (6977 eV), and XAFS results showed that the higher levels of disorder in the nanocrystals were responsible for the relatively better chromaticity. By analyzing recent studies on the nanosized materials, we considered that the high levels of disorder in the YBO 3:Eu nanocrystals resulted from the low levels of crystallization.