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Novel Dy3+-doped GdPO4 white light phosphors with a monoclinic system are successfully synthesized by the hydrothermal method at 240℃.The strong absorption at around 147nm in the excitation spectrum is assigned to the host absorption.It is suggested that the vacuum ultraviolet excited energy is transferred from the host to the Dy3+ ions.The f-d transition of the Dy3+ ion is observed to be located at 182nm,which is consistent with the calculated value using Dorenboss expression.Under 147nm excitation,Gd0.92PO4:0.08Dy3+ phosphor exhibits two emission bands located at 572 nm (yellow) and 478 nm (blue),which correspond to the hypersensitive transitions 4 F9/2-6 H13/2 and 4 F9/2-6H15/2.The two emission bands lead to the white light.Because of the strong absorption at about 147nm,Gd0.92PO4:0.08Dy3+ under vacuum ultraviolet excitation is an effective white light phosphor,and has promising applications to mercury-free lamps.