Key Factors for Template‐Oriented Porous Titania Synthesis: Solvents and Catalysts

ACS Appl. Mater. Interfaces

et al. 2021

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Gold/titanium dioxide (Au/TiO2) nanohybrid materials have been widely applied in various fields because of their outstanding optical and photocatalytic performance. By state-of-the-art polymer templating, it is possible to make uniform nanostructured TiO2 layers with potentially large-scale processing methods. We use customized polymer templating to achieve TiO2 nanostructures with different morphologies. Au/TiO2 hybrid thin films are fabricated by sputter deposition. An in-depth understanding of the Au morphology on the TiO2 templates is achieved with in situ grazing-incidence small-angle X-ray scattering (GISAXS) during the sputter deposition. The resulting Au nanostructure is largely influenced by the TiO2 template morphology. Based on the detailed understanding of the Au growth process, characteristic distances can be selected to achieve tailored Au nanostructures at different Au loadings. For selected sputter-deposited Au/TiO2 hybrid thin films, the optical response with a tailored localized surface plasmon resonance is demonstrated.

Section: Resultsmentioning

confidence: 99%

Tailoring the Optical Properties of Sputter-Deposited Gold Nanostructures on Nanostructured Titanium Dioxide Templates Based on In Situ Grazing-Incidence Small-Angle X-ray Scattering Determined Growth Laws

Liang

Chen

ACS Appl. Mater. Interfaces

et al. 2021

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“…Among the different approaches of templating titania nanostructures, copolymerassisted sol-gel synthesis has been shown to provide a facile way toward a controlled morphology also for films. [19][20][21][22][23] Furthermore, solution processing based on copolymer-assisted sol-gel synthesis has shown high promise for economically producing nanostructured titania films via largescale deposition techniques, such as slot-die coating [24][25][26] and spray deposition. [27][28][29] However, the synthetic copolymer templating routine comes along with comparatively toxic, harmful, or flammable organic solvents as well as a low sustainability.…”

Section: Introductionmentioning

confidence: 99%

Low‐Temperature and Water‐Based Biotemplating of Nanostructured Foam‐Like Titania Films Using ß‐Lactoglobulin

Heger

Chen

et al. 2022

Adv Funct Materials

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Given the broad use of nanostructured crystalline titania films, an environmentally friendly and more sustainable synthesis route is highly desirable. Here, a water-based, low-temperature route is presented to synthesize nanostructured foam-like crystalline titania films. A pearl necklace-like nanostructure is introduced as tailored titania morphology via biotemplating with the use of the major bovine whey protein ß-lactoglobulin (ß-lg). It is shown that titania crystallization in a brookite-anatase mixed phase is promoted via spray deposition at a comparatively low temperature of 120 °C. The obtained crystallites have an average grain size of (4.2 ± 0.3) nm. In situ grazing incidence small-angle and wide-angle X-ray scattering (GISAXS/GIWAXS) are simultaneously performed to understand the kinetics of film formation and the templating role of ß-lg during spray coating. In the ß-lg:titania biohybrid composites, the crystal growth in semicrystalline titania clusters is sterically directed by the condensing ß-lg biomatrix. Due to using spray coating, the green chemistry approach to titania-based functional films can be scaled up on a large scale, which can potentially be used in photocatalytic processes or systems related to energy application.

“…Related research in our group demonstrated the prominent influence of the PS-b-P 4 VP concentration on the ZnO morphology and the solvent effect during the polystyrene-block-polyethylene oxide (PS-b-PEO) templated TiO 2 and SnO 2 synthesis. [26,34,35] The formation of thermodynamically stable block polymer micelles is mainly governed by the following three contributions: The stretching degree of the core-forming polymer chains, the interfacial tension between the micelle core and the surrounding solvent, and the repulsive interactions among corona-forming chains. [25] The first two contributions can be affected by factors including copolymer composition and concentration, poor solvent content in the solution, and the preferential affinity of the common solvent.…”

Section: Introductionmentioning

confidence: 99%

“…Related research in our group demonstrated the prominent influence of the PS‐b‐P 4 VP concentration on the ZnO morphology and the solvent effect during the polystyrene‐block‐polyethylene oxide (PS‐b‐PEO) templated TiO 2 and SnO 2 synthesis. [ 26,34,35 ]…”

Section: Introductionmentioning

confidence: 99%

Multidimensional Morphology Control for PS‐b‐P₄VP Templated Mesoporous Iron (III) Oxide Thin Films

Cao

et al. 2021

Adv Materials Inter

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nanostructured α-Fe 2 O 3 exhibits more size-dependent properties induced by the high surface area and quantum confinement. [5][6][7][8] Assembly of α-Fe 2 O 3 nanoparticles (NPs) into periodic arrays has attracted high attention due to their potential applications in photoelectrochemical conversion, [9,10] photovoltaic devices, [11][12][13][14] lithium-ion batteries, [4,7,8,[15][16][17] gas sensors, [6,18,19] and high-density nanoelectronic technologies. [20,21] Here the morphology is of particular relevance. For example, when used as the electron transport layer for photovoltaic devices, the nanoscale morphology will affect the charge carrier transport and thereby the device efficiency. [22] Current lithographic techniques employed in the microelectronic industry face the escalating production cost by further decreasing the feature size. [23][24][25] As an inexpensive alternative, the block copolymer templated sol-gel method can achieve various nanoscale structures with the assistance of selfassembly of block copolymers. [2,20,[26][27][28][29][30] Typically, nanopatterning of the Fe 2 O 3 NPs through block copolymer templates can be categorized into two types: directly accommodating the NPs inside the block copolymer matrix or in situ reducing block copolymer coordinated metal precursors into NPs. To accommodate the NPs, a special surface treatment of the NPs Mesoporous α-Fe 2 O 3 thin films with large area homogeneity demonstrate tremendous potential in multiple applications. In the present work, the synthesis of morphology-controlled α-Fe 2 O 3 thin films is realized with polystyrene-blockpoly(4-vinyl pyridine) (PS-b-P 4 VP) diblock copolymer assisted sol-gel chemistry. The solvent category (DMF and 1,4-dioxane) and polymer-to-FeCl 3 ratio used for the solution preparation are systematically varied to tune the morphology of the thin films. For both solvents, DMF and 1,4-dioxane, nanocluster structures are obtained with low PS-b-P 4 VP concentration. When the concentration of PS-b-P 4 VP reaches the critical micelle concentration, spherical and wormlike porous structures are specifically formed in the DMF and 1,4-dioxane solvent system, respectively. Further increasing the polymer-to-FeCl 3 ratios leads to the enlargement of the spherical pore sizes in the DMF system, whereas the center-to-center distances of the wormlike structures in the 1,4-dioxane system decrease. Moreover, DMF/1,4-dioxane solvent mixtures with different volume ratios are applied for the sol-gel solution preparation to gain more insight into how the solvent selectivity affects the thin film morphology. By adjusting the preferential affinity of the solvent mixture to the polymer blocks, a spherical to wormlike pore shape transition is observed with a critical Δχ value of around 0.77.