Strong violet emission and optical power limiting properties of reduced graphene oxide/MoO3 synergistic composites

Abstract

Herein, we report the synthesis of reduced graphene oxide/molybdenum oxide (rGO/MoO3) via a simple precipitation method to improve the optical nonlinearity of MoO3. The successful materialization of composites was confirmed through x-ray diffraction, Raman spectroscopy, and field emission scanning electron microscopy studies. Rietveld refinement was done for the prepared samples to study the structural analysis. The optical studies revealed strong UV absorption and strong violet emission under 330 nm excitation. The mechanism of violet, blue, and green emissions from MoO3 is proposed through molybdenum interstitial related defects. The variation of bandgap in rGO/MoO3 composites was explained by the graphene induced strain on MoO3. The phonon lifetime of each sample was calculated, and it was found to decrease with respect to the rGO concentration, which makes this composite material potentially applicable for several electronic and optical applications. Moreover, energy dependent optical power limiting properties of the prepared MoO3 and rGO/MoO3 nanocomposites were measured by open aperture z-scan using nanosecond Nd-YAG pulsed laser operating at 532 nm excitation. It is found that the rGO/MoO3 nanocomposites have better optical power limiting properties with a good two photon absorption coefficient of 9.0 × 10−10 m/W. This could be attributed to the efficient interfacial charge transfer between MoO3 and rGO.