Delving into the effect of ZnO nanoparticles on the chemistry and electronic properties of aminated graphene: Ab initio and experimental probing

The emerging versatile realm of graphene/metal oxide nanoparticles (NPs) composites has boosted the development of energy storage and gas sensing systems. However, with the advancements in deriving composites of more complex designs, the explicit understanding of their physics with respect to chemistry and morphology began to fade. Here, we aspire to hint at the effect of ZnO nanoparticles on aminated graphene, bundling theoretical modeling with thorough experimental examination (Transmission electron microscopy, X-ray photoelectron, X-ray absorption fine structure and valence-band photoemission spectroscopies, and temperature-dependent sheet resistance measurements). Starting with setting up the framework for modeling the Am-ZnO composite with its thorough verification by experimental probing, we stepwise examine the material’s properties. The effect of ZnO surface chemistry on bonding, often neglected theoretically, is highlighted by core-level spectroscopy. In turn, band structure and charge localization alterations induced by ZnO NPs are pointed out experimentally, supplemented with the developed method for conductivity calculations. Given these results, the role of graphene, NPs, and their interface in chemiresistive signal appearance is further featured. Taken together, our results give a hint at the mechanisms underlying the interaction between the metal oxide NPs and derivatized graphene, advancing the engineering of such composites for practical applications.