Deposition of Au nanoshells on thermally grown patterned Ag nanoparticles from the block copolymer micelle thin films by seeding method

Acharya, H. N.

doi:10.1016/j.reactfunctpolym.2016.06.004

Cited by 4 publications

(2 citation statements)

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“…Examples of reducing agents for the growth of (quasi-spherical) Au NPs in solution include ascorbic acid, , hydroquinone, , hydroxylammonium chloride, , and hydrogen peroxide. , However, the same principle can also be applied to Au nanostructures supported on a substrate. Area-selective deposition of gold on pre-existing Au or Ag NPs, using hydroxylammonium chloride or ascorbic acid as the reducing agent, has been demonstrated previously. ,− Fabrication of highly ordered arrays of Au–Ag core–shell NPs using hydroquinone or Tollens’ reagent to grow Ag shells around Au seed particles has also been described in the literature. − Photocatalytic reduction, instead of reduction using a chemical reducing agent, is yet another approach utilized for enlarging Au NPs seated on a substrate. − Growth protocols demonstrated to be applicable on highly ordered surface supported arrays of seed particles, implemented using block copolymer lithography or block copolymer micellar lithography, are of particular interest as these lithography techniques offer a rapid and inexpensive method to pattern large-area substrates. ,,,− …”

Section: Introductionmentioning

confidence: 95%

“… 22 − 26 Growth protocols demonstrated to be applicable on highly ordered surface supported arrays of seed particles, implemented using block copolymer lithography or block copolymer micellar lithography, are of particular interest as these lithography techniques offer a rapid and inexpensive method to pattern large-area substrates. 13 , 14 , 17 , 19 − 24 …”

Section: Introductionmentioning

confidence: 99%

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Seeded Growth of Large-Area Arrays of Substrate Supported Au Nanoparticles Using Citrate and Hydrogen Peroxide

2020

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While seeded growth of quasi-spherical colloidal Au nanoparticles (NPs) has been extensively explored in the literature, the growth of surface supported arrays of such particles has received less attention. The latter scenario offers some significant challenges, including the attainment of sufficient particle-substrate adhesion, growth-selectivity, and uniform mass-transport. To this end, a reaction system consisting of HAuCl 4 , citrate, and H 2 O 2 is here investigated for the growth of supported arrays of 10 nm Au seeds, derived via block copolymer (BCP) lithography. The effects of the reagent concentrations on the properties of the resultant NPs are evaluated. It is found that inclusion of citrate in the growth medium causes substantial particle desorption from Si surfaces. However, the presence of citrate also yields NPs with more uniformly circular top-view cross sections (“quasi-circular”), motivating the exploration of particle immobilization methods. We demonstrate that atomic layer deposition (ALD) of a single cycle of HfO 2 (∼1 Å), after the seed particle formation, promotes adhesion sufficiently to enable the use of citrate without the added oxide noticeably affecting the shape of the resultant NPs. The presented ALD-based approach differs from the conventional sequence of depositing the adhesion layer prior to the seed particle formation and may have advantages in various processing schemes, such as when surface grafting of brush layers is required in the BCP lithography process. A proof-of-concept is provided for the growth of large-area arrays of supported “quasi-circular” Au NPs, in a rapid one-step process at room temperature.

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