One-Step Preparation of Silver Hexagonal Microsheets as Electrically Conductive Adhesive Fillers for Printed Electronics

Abstract

A facile one-step solution-phase chemical reduction method has been developed to synthesize Ag microsheets at room temperature. The morphology of Ag sheets is a regular hexagon more than 1 μm in size and about 200 nm in thickness. The hexagonal Ag microsheets possess a smoother and straighter surface compared with that of the commercial Ag micrometer-sized flakes prepared by ball milling for electrically conductive adhesives (ECAs). The function of the reagents and the formation mechanism of Ag hexagonal microsheets are also investigated. For the polyvinylpyrrolidone (PVP) and citrate facet-selective capping, the Ag atoms freshly reduced by N2H4 would orientationally grow alone on the {111} facet of Ag seeds, with the synergistically selective etching of irregular and small Ag particles by H2O2, to form Ag hexagonal microsheets. The hexagonal Ag microsheet-filled epoxy adhesives, as electrically conductive materials, can be easily printed on various substrates such as polyethylene terephthalate (PET), epoxy, glass, and flexible papers. The hexagonal Ag microsheet filled ECAs demonstrate lower bulk resistivity (approximately 8 × 10(-5) Ω cm) than that of the traditional Ag micrometer-sized-flake-filled ECAs with the same Ag content of 80 wt % (approximately 1.2 × 10(-4) Ω cm).

Synthesis of silver nanoplate based two-dimension plasmonic platform from 25 nm to 40 μm: growth mechanism and optical characteristic investigationin situ

“…It is also observed that pure SNP solution with an LSPR band longer than 600 nm appears blue. Interestingly, a green color which is the usual color of SNP solution 18,19,24 was absent. Actually, the green color is due to a color mixture effect of blue color representing large SNPs and yellow color representing spherical by-products which was difficult to avoid, reecting their impurity.…”

“…S6 † show that the thickness of SNP type III is between 10-60 nm (mean 30 nm) which is much thinner than that of previous reports. [18][19][20]22 SNPs with a size larger than 10 mm can be easily observed. A SNP with a size of $40 mm and an ultra-high aspect ratio of over 1000 : 1 was observed, as shown in Fig.…”

“…Many efforts have been applied to the synthesis of SNPs with single-crystalline structure using wet-chemical synthesis, [14][15][16][17][18][19][20][21][22][23][24] especially SNPs with large size. [14][15][16][17][18][19][20][21] Among those reported methods, the multi-step synthesis of SNPs in aqueous environment [22][23][24] is superior in structural uniformity, size and thickness control. Large SNPs with a high aspect ratio were expected to be obtained by the continual increment of reaction cycles.…”

Conductive sizing for improving electrical conductivity of carbon fiber/polyaryl ether ketone/AgNWs composites

“…The electrical functionalization was established by two methods: (1) the functionalization of the sizing, that was achieved by dispersing silver nanoplates into the PEI; and (2) the dispersion of silver nanowires into the matrix with CF sized with the previously mentioned functionalized sizing. To our knowledge, silver nanoplates have been only used for their optical properties, and in some rare cases as conductive filler, but never used in high performance thermoplastic matrices such as PAEK. Both mechanical and electrical properties of the different composites have been compared.…”

The hydrothermal synthesis of ultra-high aspect ratio Ag nanoflakes and their performance as conductive fillers in heaters and pastes

“…Due to their unique physical and chemical properties, silver nanomaterials have attracted extensive attention in elds such as optoelectronics, [1][2][3][4] optics, 5,6 SERS, [7][8][9][10][11] conductive pastes, [12][13][14][15][16] and heaters. 17,18 It was found that morphology, size, and crystallinity strongly affect the performance of Ag nanomaterials, and great efforts have been made towards obtaining Ag nanostructures with specic morphologies such as dendrites, 19 nanowires, 20 nanorods, 21 nanocubes, 22 and nanoakes.…”