Adsorption of Polarized Molecules for Interfacial Band Engineering of Doped TiO₂Thin Films

Abstract

Owing to their chemical and mechanical stability, metal-oxides have emerged as potential alternatives for conventional pure-metal and organic molecule-based solid-state electronic devices. Traditionally, band engineering of these metal-oxides has been performed to improve the efficiency of solar cells and transistors. However, recent advancements in the field of oxide-based electronic devices demand reversible band structure engineering for applications in next-generation adaptive electronics and memory devices. Therefore, this work aims to reversibly engineer the surface band structure of doped metal-oxides using stable organic ligands with weak dipoles. Para-substituted benzoic acid (BZA) ligands with positive and negative dipole moments were adsorbed in situ on the surface of TiO2:Ni2+ thin film to modify the interfacial dipole moment, and the valence band structure was probed using surface-sensitive ultraviolet photoelectron spectroscopy (UPS). UPS, paired with density functional theory (DFT) simulations, demonstrate the ability to selectively tune interfacial electronic/chemical landscapes with ligand-dependent dipole moment. The unique ability to reversibly tune the band bending at the organic–inorganic interface of doped metal-oxide semiconductors using molecular dipoles is expected to play a key role in the development of metal-oxide-based adaptive electronics that outperform the conventional polymer-based and Si-based devices.

DFT Study of The Interaction Characteristics Between the Organic Matter and Minerals In Coal-Series Kaolin

“…Based on our previous work, we have preliminarily analyzed the composition and structural units of organic matter in the coal-series kaolin of Yichang, China [1,20]. So in this work, on account of the mineral composition in the coal-series kaolin, we will build the adsorption models between typical organic molecule and the coal-series kaolin by Density functional theory (DFT) methods, so as to reveal the occurrence state and stability differences of different organic matters on the coal-series kaolin, fully understand the interaction mechanism between organic matter and different minerals in coal series kaolin, which can be bene cial to the enrichment and recovery of organic matter, so as to further solve the bottleneck problem of restricting the whiteness and comprehensive utilization of coal-series kaolin [19,21,22].…”