NIR emission and energy transfer phenomena in Bi2(MoO4)3 doped with Nd3+and/or Yb3+

Abstract

Phosphors based on Bi2(MoO4)3 host and Nd3+ and/or Yb3+ activators have been prepared for the first time. Intense NIR emissions around 1 μm are observed due to characteristic lanthanide transitions. Excitation spectra reveal that the NIR emissions are host sensitized. Bi2(MoO4)3 is a semiconductor with a band gap of the order of 2.8 eV showing intense absorption in nUV-violet region. In addition to host sensitization, Yb3+ emission is also sensitized by Nd3+ → Yb3+ energy transfer. These phosphors are thus characterized by strong, broad band excitations in nUV-violet region and NIR emissions around 1 μm. It is argued that these are suitable as spectrum modifier for enhancing solar cell performance. In addition to the nUV-violet absorption, Nd3+ doped phosphors show intense absorption arising from f-f transitions covering the range 470-890 nm. This makes them suitable for applications in solar pumped lasers.