Evidence of non-radiative energy transfer from the host to the active ionsin monoclinic ZrO2 : Sm3+

We present the photoluminescence characterization of pure and 0.2 mol% sama rium-doped zirconium oxide, prepared by the sol-gel process and annealed at 1000 degreesC to stabilize the monoclinic phase. Under excitation at 320 m n the Sm3+-doped monoclinic zirconium oxide shows strong emission at the gr een (569 nm) and red (607, 613 and 618 nm) bands, corresponding to the (4)G (7/2) --> H-6(9/2) and F-4(3/2) --> H-6(9/2) samarium transitions, respecti vely; whereas the undoped sample only shows a broadband emission centred at 495 nm. The main mechanism that allows the samarium emission under U-V exc itation appears to be non-radiative energy transfer from the ZrO2 host to t he Sm3+ ions.