Realization of tunable emission via efficient Tb~(3+)-Eu~(3+) energy transfer in K_3Gd(PO_4)_2 for UV-excited white light-emitting-diodes

摘要

A n-UV convertible phosphor K_3Gd(PO_4)_2:Tb~(3+), Eu~(3+) with tunable-emitting color has been synthesized by the solid state reaction. Under the Tb~(3+) excitation (373 nm), the Eu~(3+) emissions increase dramatically with increasing the Eu~(3+) content due to the efficient energy transfer from Tb~(3+) to Eu~(3+), which has been justified through the luminescence spectra and fluorescence decay curves. K_3Gd(PO_4)_2:0.5Tb~(3+), yEu~(3+) can achieve tunable color emissions from yellowish-green through orange-yellow and ultimately to reddish-orange by simply adjusting the Eu3* content. In addition, the energy transfer mechanism was demonstrated to be the dipole-dipole interaction and the energy transfer efficiency was calculated. The present results indicate that this novel orange-yellow emitting phosphor can be as a potential candidate for the application in white LEDs.