Enhanced Red Emission in Sr2CeO4: Eu3+ by Charge Compensation

Abstract

A series of Eu3+ doped Sr2CeO4 without or with different charge compensators (Li+, Na+, K+ and Al3+) were prepared by solid state reactions. The phosphors can strongly absorb ultraviolet (broad band overlapping 254 nm) which is coupled well with the emission of low pressure mercury vapor lamps. The optimal doping concentration of Eu3+ in Sr2CeO4 is experimentally ascertained to be 13 mol %. Varying charge compensators influence the relative luminescent intensity rather than the shape and position of excitation and emission spectra in the same host lattices. The introduction of K+ can enhance the red emission intensity of Eu3+ by ∼2 times with the optimal effect. The other three charge compensators (Li+, Na+ and Al3+) can also enhance the emission of Eu3+. However, their effects are not as good as K+ because they can not relieve the volume unbalance while net positive charge was offset. Therefore, when a charge compensator is selected, volume compensation should also be taken into account. The investigation also shows that Eu3+ doped Sr2CeO4 phosphors with charge compensation are potential candidates of red emitting phosphors for low pressure mercury lamp or AlxGa1−xN-based UV LEDs.