Development of persistent phosphors by using electron transfer process
Jumpei UEDA1, Setsuhisa TANABE1
Ce3+-doped garnet materials have attracted a great deal of attention in LED applications because of their novel optical properties. To investigate the quenching process, the photocurrent by blue light excitation in Y3Al5-xGaxO12:Ce3+ phosphors was measured. Based on the photoconductivity results, it was concluded that Y3Al2Ga3O12:Ce3+ luminescence is quenched by thermally-assisted photoionization. Utilizing the thermally assisted photoionization by blue light excitation and introducing the electron trap center, we successfully developed a blue light chargeable persistent phosphor in Y3Al2Ga3O12:Ce3+-Cr3+. From the constructed VRBE (vacuum referred binding energy) diagram, Yb3+ ion was predicted as an appropriate electron trap and Ce3+-Yb3+ co-doped Y3Al2Ga3O12 showed the long persistent luminescence.
- 1 Graduate School of Human and Environmental Studies