Laser Driven In Situ Growth of Metal Nanoparticles on Graphene Oxide Nanosheets for Plasmon-Enhanced Optoelectronic Responses

Abstract

Graphene's exceptional efficacies for optoelectronic and photonic applications have captivated the world toward technological advancements. However, its atomic-scale thickness impedes light− matter interactions and limits device performances. Recently, graphene adorned with metallic nanoparticles has gained huge attention for its potential to improve the optical absorption in a broad spectral range. Herein, we have enhanced the optical absorption by in situ grown silver and gold nanoparticles on simultaneously reduced graphene oxide nanosheets using nanosecond laser pulses. Plasmon field distributions and interfacial interactions were simulated through finite difference time domain calculations for hybrids, as well as individual metal nanoparticles. Also, extinction cross sections of nanoparticles and reduced graphene oxide nanosheets along with hybrids were simulated to compare with the experimental results, and we found an enriched optical response due to the interaction of the localized plasmon resonance band of metal nanoparticles with broad absorption of reduced graphene oxide nanosheets. We explored the I−V characteristics, particularly at surface plasmon resonance wavelengths, to capture the plasmon effect on device performance and found an enhanced photocurrent for hybrids. The charge transfer and free carrier absorption in these hybrids have shown a giant nonlinear optical absorption in the nanosecond regime. The observed optoelectronic responses of these hybrid materials are wellsuited for light sensing and optical safety devices.