Optical and surface morphological studies on CuPcOC8 thin films prepared by physical vapour deposition

Vadakel, Vinu. T.; Menon, C. S.

doi:10.2478/s13536-013-0117-5

Cited by 4 publications

(3 citation statements)

References 36 publications

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“…A material’s surface texture affects local surface area and surface energy and hence has tremendous effect on its utility . The effect of surface texture has inspired advances like superhydrophobic/superhydrophilic and self-cleaning materials. − High surface area also affects adsorption of small molecules and particles, hence, potential applications in catalysis and drug delivery. − Most methods that modify surface texture are additive, − subtractive, − or a combination of both. − Additive methods rely on introduction of chemi- or physisorbed adducts on the surface, whereas subtractive methods achieve this goal by selective partial removal of material to alter surface features. In addition, top-down, − bottom-up, , and interfacial methods − are also utilized to obtain characteristic surface patterns.…”

Section: Introductionmentioning

confidence: 99%

Autonomous Thermal-Oxidative Composition Inversion and Texture Tuning of Liquid Metal Surfaces

et al. 2018

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Droplets capture an environment-dictated equilibrium state of a liquid material. Equilibrium, however, often necessitates nanoscale interface organization, especially with formation of a passivating layer. Herein, we demonstrate that this kinetics-driven organization may predispose a material to autonomous thermal-oxidative composition inversion (TOCI) and texture reconfiguration under felicitous choice of trigger. We exploit inherent structural complexity, differential reactivity, and metastability of the ultrathin (∼0.7-3 nm) passivating oxide layer on eutectic gallium-indium (EGaIn, 75.5% Ga, 24.5% In w/w) core-shell particles to illustrate this approach to surface engineering. Two tiers of texture can be produced after ca. 15 min of heating, with the first evolution showing crumpling, while the second is a particulate growth above the first uniform texture. The formation of tier 1 texture occurs primarily because of diffusion-driven oxide buildup, which, as expected, increases stiffness of the oxide layer. The surface of this tier is rich in Ga, akin to the ambient formed passivating oxide. Tier 2 occurs at higher temperature because of thermally triggered fracture of the now thick and stiff oxide shell. This process leads to inversion in composition of the surface oxide due to higher In content on the tier 2 features. At higher temperatures (≥800 °C), significant changes in composition lead to solidification of the remaining material. Volume change upon oxidation and solidification leads to a hollow structure with a textured surface and faceted core. Controlled thermal treatment of liquid EGaIn therefore leads to tunable surface roughness, composition inversion, increased stiffness in the oxide shell, or a porous solid structure. We infer that this tunability is due to the structure of the passivating oxide layer that is driven by differences in reactivity of Ga and In and requisite enrichment of the less reactive component at the metal-oxide interface.

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Section: Introductionmentioning

confidence: 99%

Autonomous Thermal-Oxidative Composition Inversion and Texture Tuning of Liquid Metal Surfaces

et al. 2018

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“…C 60 -CuPcOC 8 demonstrates exceptional hydrogen evolution activity, achieving a rate of 8.32 mmol•g −1 •h −1 . The introduction of octoctyloxy modification to CuPc is aimed at enhancing the solubility of phthalocyanine in organic solvents and allowing for the fine-tuning of the physicochemical properties of phthalocyanine derivatives [33]. The non-covalently supramolecular photocatalyst C 60 -CuPcOC 8 was obtained by using the liquid-liquid interface precipitation method.…”

Section: Introductionmentioning

confidence: 99%

Efficient Charge Separation and Transport in Fullerene-CuPcOC8 Donor–Acceptor Nanorod Enhancing Photocatalytic Hydrogen Generation

Hua,

Wu,

Zhang

et al. 2024

Nanomaterials

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Photocatalytic hydrogen generation via water decomposition is a promising avenue in the pursuit of large-scale, cost-effective renewable hydrogen energy generation. However, the design of an efficient photocatalyst plays a crucial role in achieving high yields in hydrogen generation. Herein, we have engineered a fullerene-2,3,9,10,16,17,23,24-octa(octyloxy)copper phthalocyanine (C60-CuPcOC8) photocatalyst, achieving both efficient hydrogen generation and high stability. The significant donor–acceptor (D–A) interactions facilitate the efficient electron transfer from CuPcOC8 to C60. The rate of photocatalytic hydrogen generation for C60-CuPcOC8 is 8.32 mmol·g−1·h−1, which is two orders of magnitude higher than the individual C60 and CuPcOC8. The remarkable increase in hydrogen generation activity can be attributed to the development of a robust internal electric field within the C60-CuPcOC8 assembly. It is 16.68 times higher than that of the pure CuPcOC8. The strong internal electric field facilitates the rapid separation within 0.6 ps, enabling photogenerated charge transfer efficiently. Notably, the hydrogen generation efficiency of C60-CuPcOC8 remains above 95%, even after 10 h, showing its exceptional photocatalytic stability. This study provides critical insight into advancing the field of photocatalysis.

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“…Vapor Deposition (PVD) 28,29 , Chemical Vapor Deposition (CVD) [30][31][32][33][34] , and electrospray deposition 35 , for example as shown by the change in surface morphology of InN films with deposition temperature (Figure 2a…”

Section: Most Additive Physical Methods Include An Array Of Depositiomentioning

confidence: 99%

Tuning surface texture of liquid metal particles by exploiting material metastability

Cutinho

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Surface roughness, and associated changes in properties, often dictate how a material is utilized or manifests unprecedented capabilities to well-known materials. Most approaches to engineer surface texture are, however, predominantly based on additive and/or subtractive routes that are often either; i) inefficient (arduous, lengthy and expensive), or ii) inaccessible (due to a need for specialized equipment and skilled manpower). Understanding a materials interface structure at the sub-nanometer scale, and pairing this with its thermodynamic landscape, offers a new frugal approach to engineer its surface texture. Herein, we demonstrate thermal-driven evolution of surface morphology by exploiting inherent structural complexity, and metastability, of the ultra-thin passivating oxide on liquid metal particles. We achieve tunable surface texture via thermal-triggered oxidation of the liquid, whereby structural order on the surface was controlled through kinetics (reduction potentials of constituent elements) and stoichiometry, the latter being driven by interfacial phase-segregation upon oxidation. Release of the underlying phasesegregated components lead to inversion in the composition of the surface of these metal oxides, with concomitant growth in the thickness of the passivating layer. We divide our study in two parts viz; i) utilizing a thermodynamically stable core with a metastable shell, and ii) engineering liquid metal particles with metastable core and a metastable interface. For the former case, we obtained particles characterized by crumples, patches and multi-tiered roughness with increase in processing temperature and time. The overall structure of the particle evolves from a smooth sphere into a crumpled sphere and eventually a textured surface with increasing temperature while retaining the liquid core. At temperatures >1173 K, the liquid core is not observed but a hollow solid particle is formed with significant inter-particle sintering. For particles with metastable core vi and metastable interfaces, we observed greater effects of thermal stress due to phase change. The particles undergo spinodal decomposition upon solidification while differences in thermal expansivities of the constituent elements led to dendritic growth, albeit after a specific trigger temperature.

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Optical and surface morphological studies on CuPcOC8 thin films prepared by physical vapour deposition

Cited by 4 publications

References 36 publications

Autonomous Thermal-Oxidative Composition Inversion and Texture Tuning of Liquid Metal Surfaces

Autonomous Thermal-Oxidative Composition Inversion and Texture Tuning of Liquid Metal Surfaces

Efficient Charge Separation and Transport in Fullerene-CuPcOC8 Donor–Acceptor Nanorod Enhancing Photocatalytic Hydrogen Generation

Tuning surface texture of liquid metal particles by exploiting material metastability

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