Blue-green tunable electroluminescence from Y2SiO5:Tb3+ phosphor

Terbium (Tb3+)-doped materials have gained interest due to their unique tunable optical properties in photoluminescence (PL) attributed to the cross-relaxation process. In this application, various emission colors can be obtained by tuning the Tb3+ concentration. Herein, a tunable blue-green Y2SiO5:Tb3+ powder-based electroluminescent (PEL) device was demonstrated through a facile screen-printing method prepared by a solid-state reaction. The phosphor powder formed as X2-phase Y2SiO5 and is dispersed in an ethyl cellulose binder before being screen-printed in an ITO glass substrate. The cross-sectional image revealed that the Y2SiO5:Tb3+ PEL device consists of 20 μm-thick BaTiO3 as an insulating layer and 10 μm-thick X2-phase Y2SiO5:Tb3+ as an active layer. Under the sinusoidal alternating current, it emits tunable blue-green color with dominance peaks at 416 nm and 543 nm depending on the Tb3+ concentration, which is optically attributed to f-f transitions of Tb3+ ions. In particular, the EL intensity was gradually increased according to the voltages, frequencies, and temperatures before suffering a thermally quenched above 100 °C (373 K). Additionally, the Y2SiO5:Tb3+ PEL device emits an ultraviolet-A (380 nm) spectrum, which could be used for sterilization applications.