Fine Tuning the Microenvironment of [Euw10o36]9- Anion Leads to the Large Enhancement of the Red Light Luminescence

Abstract

The polyoxometalate (POM) anion of europium (III) decatungstate [EuW10O36]9- exhibits great luminescence quantum yields of approximately 67% but suffers reduced red light emissions that are due to the low 5D0→7F2 transmissions. Fine tuning the microenvironment around [EuW10O36]9- anion through intercalation into different compositions of layered double hydroxides (LDHs) materials, greatly enhances the 5D0→7F2 transmissions. The positive nanosheets in LDHs provide a conducive microenvironment for strong transitions of 5D0→7F2 to occur. The ratio I(5D0→7F2)/I(5D0→7F1) for the observed intensities vary from 0.44 for [EuW10O36]9- ion to 14.08, 6.20, 1.75 and 1.59 in Mg2Al-EuW10O36, LYbH-EuW10O36, Zn2Al-EuW10O36 and LEuH-EuW10O36 materials respectively (Mg2Al = magnesium aluminum LDHs, Zn2Al = Zinc aluminum LDHs, LYbH = layered ytterbium hydroxide LDHs, and LEuH = layered europium hydroxide LDHs). As such, these materials can find a wide application in processes that require the red light luminescence.