Tuning the emission colour in mixed lanthanide microporous silicates: energy transfer, composition and chromaticity
The Ln-AV-20 structure is able to incorporate several different Ln3+ ions, which emit in different spectral regions, enabling the possibility of multi-colour capability. Using a study of the energy transfer dynamics in Gd1−(a+b)TbaEub-AV-20 materials, we show that the emission chromaticity of these systems may be fine-tuned in the red–green spectral region simply by changing the excitation wavelength and/or the sample composition. We show that a study of the energy transfer kinetics, in these and in related materials, can provide useful insight when the design of a material with a specific emission profile is required. By replacing Gd3+ with Ce3+, a system with full-colour capability, Ce0.53Tb0.35Eu0.12-AV-20, has been prepared. The emission colour coordinates for this material at room-temperature are x,y = 0.34, 0.33, which is in good agreement with the values given by the CIE for a white standard.