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

Priya V Tumram,P D Belsare,S P Wankhede,Pranay R Kautkar,S V Moharil

doi:10.1063/1.5112135

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.

Highlights

Phase diagram of Bi2O3-MoO3 system is very rich, a large variety of phases are known
NIR emission in Bi2(MoO4)[3] host containing Nd3+ and Yb3+ activators has been reported for the first time
Emission intensities are limited by concentration quenching which results from energy transfers between similar lanthanide ions (Nd3+ →Nd3+, Yb3+ →Yb3+)

Summary

INTRODUCTION

Phase diagram of Bi2O3-MoO3 system is very rich, a large variety of phases are known. Apart from these better known phases, compounds like Bi4MoO9, Bi6MoO12 have been prepared.[1] As many as eight formulae have been mentioned by Egashira et al.[2] α, β and γ bismuth molybdates can absorb visible light (420 nm to 500 nm) owing to smaller bandgap (2.5 eV to 2.9 eV), and exhibiting photocatalytic activity which is useful for removal of organic pollutants These have been studied for more than fifty years for their photocatalytic activities and associated applications like dye degradation, water splitting, photosynthesis by partial oxidation and ammoxidation,[3] etc. Results on these phosphors are described in the present paper

EXPERIMENTAL

RESULTS AND DISCUSSIONS

CONCLUSIONS