On the Fate of Lithium Ions in Sol–Gel Derived Zinc Oxide Nanocrystals

Abstract

Among diverse chemical synthetic approaches to zinc oxide nanocrystals (ZnO NCs), ubiquitous inorganic sol–gel methodology proved crucial for advancements in ZnO‐based nanoscience. Strikingly, unlike the exquisite level of control over morphology and size dispersity achieved in ZnO NC syntheses, the purity of the crystalline phase, as well as the understanding of the surface structure and the character of the inorganic–organic interface, have been limited to vague descriptors until very recently. Herein, ZnO NCs applying the standard sol–gel synthetic protocol are synthesized with zinc acetate and lithium hydroxide and tracked the integration of lithium (Li) cations into the interior and exterior of nanoparticles by combining various techniques, including advanced solid‐state NMR methods. In contrast to common views, it is demonstrated that Li+ ions remain kinetically trapped in the inorganic core, enter into a shallow subsurface layer, and generate “swelling” of the surface and interface regions. Thus, this work enabled both the determination of the NCs’ structural imperfections and an in‐depth understanding of the unappreciated role of the Li+ ions in impacting the doping and the passivation of sol–gel‐derived ZnO nanomaterials.

Magnetron sputtering as a solvent-free method for fabrication of nanoporous ZnO thin films for highly efficient photocatalytic organic pollution degradation

“…Based on the most commonly used approaches we can propose the division to vacuum and chemical methods, both of which have their own advantages and yield different properties of the materials. (2,(10)(11)(12) The chemical methods focus mainly on obtaining nanostructured ZnO by wet methods such us sonochemical (13), sol-gel (14), solvo-or hydrothermal (15) or organometallic approaches (16,17), etc, leading to the formation of nanostructures and nanoparticles. Vacuum methods focus more on thin, uniformly dense films grown by means of atomic layer deposition (18) or epitaxial techniques (19), pulsed laser deposition (20) or magnetron sputtering (21).…”

Direct Readout of Homo- vs Heterochiral Ligand Shell of Quantum Dots

“…For example, l - and d -cysteine- , and l - and d -arginine-coated ZnO QDs were prepared by a modified sol–gel method using chiral molecules as a surface stabilizer during synthesis. However, it should be noted that the conventional sol–gel procedure is an attractive synthetic approach yet uncontrollable process leading to QDs with an ill-passivated and unstable surface and a complicated heterogeneous coating shell composed. − Significant progress to the field has been made thanks to the one-pot self-supporting organometallic (OSSOM) procedure, a general synthetic method based on the controlled exposure of [RZn­(X)]­n-type (X = monoanionic organic ligand) precursors to air at ambient temperature. , The OSSOM approach allowed the preparation of a series of QDs with both a homochiral organic shell composed of strongly anchored enantiomerically pure aminoalcoholate capping ligands, and subnanometer control of size with diameters below 10 nm that are well suited for investigating size-dependent optical properties . The chiroptical responses originated from the multipoint interactions of aminoalcoholate ligands with the surface through the amine nitrogen and the alcoholate oxygen that can transmit an enantiomeric structural imprint on the ZnO surface.…”

“…However, it should be noted that the conventional sol–gel procedure is an attractive synthetic approach yet uncontrollable process leading to QDs with an ill-passivated and unstable surface and a complicated heterogeneous coating shell composed. 58 − 60 Significant progress to the field has been made thanks to the one-pot self-supporting organometallic (OSSOM) procedure, a general synthetic method based on the controlled exposure of [RZn(X)]n-type (X = monoanionic organic ligand) precursors to air at ambient temperature. 58 , 59 The OSSOM approach allowed the preparation of a series of QDs with both a homochiral organic shell composed of strongly anchored enantiomerically pure aminoalcoholate capping ligands, and subnanometer control of size with diameters below 10 nm that are well suited for investigating size-dependent optical properties.…”