Study of energy transfer and spectral downshifting in Ce, RE (RE = Nd and Yb) co-doped lanthanum phosphate

- The Ce3+-Nd3+ and Ce3+-Yb3+ ion pair co-doped LaPO4 phosphors synthesized by conventional solid state reaction method.
- The strong NIR emissions reported at 1058 nm and 979 nm at UV excitation of 278 nm due to Nd3+ and Yb3+ ion in Ce3+ ion doped LaPO4 materials.
- The energy transfer (ET) process from Ce3+ to Nd3+ and Ce3+ to Yb3+ was studied and compared with the help of time decay curves.

The phosphors LaPO4 (Lanthanum phosphate) doped with Ce(III)/Ce3+ and co-doped with Ce3+-Nd3+ and Ce3+-Yb3+ were effectively synthesized by conventional solid state reaction method. The prepared samples were characterized by powder X-ray diffraction (XRD) and surface morphology was studied by scanning electronic microscope (SEM). The photoluminescence (PL) properties were studied by spectrophotometers in near infrared (NIR) and ultraviolet visible (UV-VIS) region. Additionally the luminescence time decay curves of samples were investigated to confirm energy transfer (ET) process. The Ce3+-Nd3+ ion co-doped LaPO4 phosphors can convert a photon of UV region (278 nm) into photons of NIR region (1058 nm). While Ce3+-Yb3+ ion doped LaPO4 phosphors convert photons of UV region (278 nm) into photons of NIR region (979 nm). The Ce3+ ion acts like sensitizer and Nd3+/Yb3+ ions act as activators. Both kinds of emissions are suitable for improving spectral response of solar cells.

85