Designer materials: Retrosynthesis of new inorganic solids, nanomaterials, and thin films with controlled structures and morphologies

Solid-state inorganic chemistry is dominated by high-temperature syntheses. As chemists seek to synthesize new materials with superior properties, subtle structural features become increasingly difficult to control thermodynamically. This thesis presents alternative low-temperature strategies for synthesizing inorganic solids and thin films.; Layered perovskite tantalates that exhibit ion exchange were synthesized by direct solid-state reactions, and their proton forms topochemically dehydrate to form A-site defective perovskites. A topochemical reduction reaction was developed to convert layered perovskites into non-defective three-dimensional perovskites. The A-site cations either disorder or remain ordered, depending on the layer charge. The anisotropic morphology of the precursors is retained. Topochemical reduction can also form layered products. CaEu₂Ti ₂O₈, formed by divalent ion exchange of the single-layer phase NaEuTiO₄, forms the non-defective double-layer phase Eu ₂CaTi₂O₇ upon reduction in hydrogen. Na₂ Ln₂Ti_3−xMn_xO ₁₀ (0 ≤ x ≤ 1) was synthesized by direct solid-state reaction, and A₂Ln₂Ti_3−xMn _xO₁₀ (A = Li, NH₄) and AIIGd ₂Ti_3−xMn_xO₁₀ (AII = Mg, Ca) are formed by ion exchange. Temperature-dependent magnetic susceptibility data suggest that most of the Na₂Ln₂Ti _3−xMn_xO₁₀ phases order magnetically at low temperatures. The single-layer phases KLnTiO₄ (Ln = lanthanide), which readily hydrate, were formed by ion exchange of HLnTiO₄ in aqueous KOH.; Protonated Dion-Jacobson phases exfoliate into nanoscale colloidal sheets upon reaction with tetra(n-butyl)ammonium hydroxide. These sheets self-assemble to form tiled monolayer and multilayer thin films on a polycation-derivatized Si/SiO₂ surface. Protonated Ruddlesden-Popper tantalates and titanotantalates exfoliate into nanoscale colloidal sheets, scrolls, and fibers, which can be used as building blocks for perovskite thin films.; When we combine the low-temperature reactions of perovskites that have been developed in the past few years, a powerful toolbox of solid-state reactions emerges. Using this toolbox, we can retrosynthetically synthesize a wide range of new layered and three-dimensional perovskites with controlled structures and morphologies.; Colloidal crystals are large-scale analogues of inorganic crystals, and they have interesting applications as photonic materials. We proposed two retrosynthetic approaches for synthesizing new colloidal crystals with controlled structures and morphologies. A layer-by-layer approach was studied for assembling colloidal crystals with non-close-packed structures. A lithographic approach was studied for forming controlled defects in colloidal crystal waveguides.