Unravelling the synergistic effect of reduced graphene oxide on optical, phonon and optical power limiting properties of rGO/α-MoO${}_3$ nanohybrids

Reduced graphene oxide (rGO) and semiconducting metal oxide nanohybrids is an emerging class of attractive candidates towards many optical and optoelectronic applications. Herein, we investigated the nonlinear optical properties of rGO/α-MoO${}_3$ nanohybrids through open aperture z scan technique under nanosecond pulses at 532 nm excitation which shows the two-photon absorption (2PA) behavior. We found that the synergistic effect between rGO and α-MoO${}_3$ plays a significant role in the enhancement of optical power limiting properties. The variation in refractive index (n) and extinction coefficient (k) of α-MoO${}_3$ and rGO/α-MoO${}_3$ were calculated using the Kramers-Kronig (K-K) equations from the optical reflectance spectroscopic studies. The effect of rGO concentration on the lifetime phonons of singly, doubly, and triply coordinated stretching vibrations of terminal oxygen was investigated from Raman spectroscopic studies. Our experimental results imply that rGO/α-MoO${}_3$ has better optical power limiting property with the highest 2PA coefficient compared to previous literature (listed in the table).