Resolving the Atomic Structure of Sequential Infiltration Synthesis Derived Inorganic Clusters

Abstract

Sequential infiltration synthesis (SIS) is a route to the precision deposition of inorganic solids in analogy to atomic layer deposition but occurs within (vs upon) a soft material template. SIS has enabled exquisite nanoscale morphological complexity in various oxides through selective nucleation in block copolymers templates. However, the earliest stages of SIS growth remain unresolved, including the atomic structure of nuclei and the evolution of local coordination environments, before and after polymer template removal. We employed In K-edge extended X-ray absorption fine structure and atomic pair distribution function analysis of high-energy X-ray scattering to unravel (1) the structural evolution of InO x H y clusters inside a poly(methyl methacrylate) (PMMA) host matrix and (2) the formation of porous In 2 O 3 solids (obtained after annealing) as a function of SIS cycle number. Early SIS cycles result in InO x H y cluster growth with high aspect ratio, followed by the formation of a threedimensional network with additional SIS cycles. That the atomic structures of the InO x H y clusters can be modeled as multinuclear clusters with bonding patterns related to those in In 2 O 3 and In(OH) 3 crystal structures suggests that SIS may be an efficient route to 3D arrays of discrete-atom-number clusters. Annealing the mixed inorganic/polymer films in air removes the PMMA template and consolidates the as-grown clusters into cubic In 2 O 3 nanocrystals with structural details that also depend on SIS cycle number.

Boosting Electrochemical Activity of Porous Transparent Conductive Oxides Electrodes Prepared by Sequential Infiltration Synthesis

“…This may further imply the complex formation of Zn 2+ ions, such as zinc carboxylates. [12,77,78] The identification of the exact structure of the Zn complexes, such as whether they are unidentate, bidentate, or bridging, will require more advanced characterization techniques, such as synchrotron X-ray based techniques [79] and 2D IR spectroscopy. [80] In addition, we performed an inductively coupled plasma-mass spectroscopy (ICP-MS) analysis of the two solutions obtained after immersing the IZO|FTO samples for 24 h. The solution containing FcCOOH was composed of 497 ppb of In and 105 ppb of Zn, whereas the solution without FcCOOH contained only a trace level of In and Zn (3 ppb).…”

Electronic Conductivity of Nanoporous Indium Oxide Derived from Sequential Infiltration Synthesis

“…Sequential infiltration synthesis (SIS) − is a vapor phase synthetic technique that may be considered a derivative of atomic layer deposition (ALD). Like ALD, SIS provides atomic-scale control over the growth of an expanding list of metal oxides that now includes SiO 2 , Al 2 O 3 , , TiO 2 , , WO, VO, ZnO, SnO 2 , Ga 2 O 3 , and In 2 O 3 . SIS differs from ALD in that the metal–organic precursor reacts within a soft material substrate by forming a relatively long-lived adduct or covalent bond with functional groups on the polymer side chains or backbone, instead of an irreversible covalent bond upon a solid substrate.…”

“…Subsequent SIS cycles may proceed via the same quenched adduct pathway or through a more ALD-like irreversible reaction with metal oxyhydroxide centers formed in previous cycles . The precision of this synthetic method results in nearly single-atom scale control of inorganic cluster size, which may allow wide tunability in the morphology and properties of derived inorganic solids …”

Bimetallic Copper/Ruthenium/Osmium Complexes: Observation of Conformational Differences Between the Solution Phase and Solid State by Atomic Pair Distribution Function Analysis

“…[6][7][8][9] By refining simulated structural models to the experimentally measured one-dimensional PDF patterns,o ne can directly visualize molecular structure. As ar esult, X-ray scattering has been extensively applied to awide variety of molecular materials including polymers, [10,11] metal oxides, [12][13][14][15][16][17][18] biomacromolecules, [19][20][21][22] aggregates of organic compounds [23][24][25] and supramolecular architectures. [26][27][28][29][30][31][32][33][34] Advancements at synchrotron X-ray sources have enabled high-energy X-ray scattering (HEXS) capabilities,which drastically expands the q range up to % 40 À1 and yields an achievable spatial resolution of % 0.1 .…”

“…By refining simulated structural models to the experimentally measured one‐dimensional PDF patterns, one can directly visualize molecular structure. As a result, X‐ray scattering has been extensively applied to a wide variety of molecular materials including polymers, [10, 11] metal oxides, [12–18] biomacromolecules, [19–22] aggregates of organic compounds [23–25] and supramolecular architectures [26–34] …”