Effect of Al3+ on the spectroscopic properties of Eu2+- and Tb3+-Doped high silica glass

In this study, Eu2+/Al3+-, Eu2+/Tb3+-, and Eu2+/Tb3+/Al3+-doped high silica glasses were prepared, and the effect of Al3+ on the spectroscopic properties of Eu2+ and Tb3+ and the energy transfer of Eu2+-> Tb3+ was investigated. The results revealed that the addition of Al3+ increased the luminescent intensity of the Eu2+-doped glass by approximately 400 times. An obvious Eu2+-> Tb3+ energy transfer occurred in the Eu2+/Tb3+-doped high silica glass, whose transfer efficiency can reached 66.9%. However, the efficiency continuously decreased as the Al3+ concentration increased, and eventually, it dropped to 7.2%. These phenomena can be explained by the following: Al3+ not only disperses Eu2+ but also changes the field strength and symmetry of its neighboring environment, thus increasing its emission intensity. Moreover, Al3+ destroys the strong dipole-dipole interactions between Eu2+ and Tb3+ in high silica glass due to its dispersive ability, which inhibits the energy transfer of Eu2+-> Tb3+. This indicates that a small amount of Al3+ can significantly modify the neighboring environment of Eu2+ and change its light-emitting characteristics, potentially yielding efficient blue and green phosphors excited by near-ultraviolet light for use in white light-emitting diodes.