New method to single-crystal micrometer-sized ultra-thin silver nanosheets: Synthesis and characterization

We reported a new method, which uses Cu ⁺ as the efficient and clean reducing agent, to synthesize micrometer-sized ultra-thin silver (Ag) nanosheets in organic solvent containing oleylamine (OAm). The as-synthesized Ag nanosheets are single-crystal, with regular triangular, truncated triangular, hexagonal, and dodecahedral (truncated hexagonal) shapes, with 3 - 8μm edge length and 25 ± 15 nm thickness, which are in contrast to the previous reported micrometer-sized metal nanosheets with thickness above 40 nm. Analysis is performed by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, UV - vis-NIR absorption and transmittanee spectroscopy, and optical microscopy, indicating that single-crystal Ag nanosheets are of high quality with a large in-plane size, ultra-thin thickness, and top and bottom enclosed by {111} facets. The present study provides a simple and extendable method to synthesis of micrometer-scale ultra-thin metal nanosheets holding promises for novel physical properties and functional nanodevices.