▎ 摘　　要

Controlling the doping levels in graphene by modifying the electric potential of interfaced nanostructures is important to understand "cascaded-doping" -based applications of graphene. However, graphene does not have active sites for nanoparticle attachment, and covalently adding functional groups on graphene disrupts its planar sp(2)-hybridization, affecting its cascaded doping. Here we show a hexahepto (eta(6)) photo-organometallic chemistry to interface nanoparticles on graphene while retaining the sp(2)-hybridized state of carbon atoms. For testing cascaded doping with ethanol interaction, transition metal oxide nanoparticles (TMONs) (Cr2O3/CrO3, MoO3, and WO3) are attached on graphene. Here, the transition metal forms six sigma-bonds and pi-back-bonds with the benzenoid rings of graphene, while its opposite face binds to three carbonyl groups, which enable nucleation and growth of TMONs. With a radius size ranging from 50 to 100 nm, the TMONs downshift the Fermi level of graphene (-250 mV; p-doping) via interfacial charge transfer. This is consistent with the blue shift of graphene's G and 2D Raman modes with a hole density of 3.78 x 10(12) cm(-2). With susceptibility to ethanol, CrxO3 nanoparticles on graphene enable cascaded doping from ethanol that adsorbs on CrxO3, leading to doping of graphene to increase the electrical resistance of the TMONs-graphene hybrid. This nanoparticle-on-graphene construct can have several applications in gas/vapor sensing, electrochemical catalysis, and high-energy-density supercapacitors.