Surface Modification of ITO Nanoparticles by Trimesic Acid: A Combined Experimental and DFT Study

Surface modification of ITO films is important for their applications in optoelectronics. Herein, trimesic acid was used to modify polycrystalline ITO nanoparticles. Spectroscopic results indicate the formation of carboxylate on the ITO nanoparticle surfaces upon modification. Density functional theory calculations reveal an upstanding adsorption structure of the acid molecule on the ITO (111) surface and the formation of a carboxylate surface species. The dissociative chemisorption of trimesic acid on the selected surface was found to be thermodynamically exothermic and kinetically facile. We show that the surface-modified ITO nanoparticles are capable of effectively enhancing the charge-transfer rate and substantially boosting electrocatalytic effect toward redox of ferrocene via a pi-pi interaction between ferrocene and the adsorbate.