Determination of the Surface Facets of Gold Nanorods in Wet‐Coated Thin Films with Grazing‐Incidence Wide Angle X‐Ray Scattering

Abstract

This work studies the surface facets of gold nanorods (AuNRs) in wet‐coated nanoparticle thin films with synchrotron‐light‐based grazing‐incidence wide angle X‐ray scattering (GIWAXS), which provides statistically relevant results on many nanoparticles. Air‐brush spraying deposits the monodisperse AuNRs into sparse monolayers where the long axis of rods is parallel to the substrate surface. It is found that the crystalline facets of individual AuNRs in the sparse monolayer are all in the same orientation, as indicated by narrow azimuthal widths of (200) reflections, over a macroscopic scale comparable to the substrate. This alignment is probably due to the rods' sitting on high‐index surface facets such as (520) and (250). A quantitative analysis of the angles between bulk facets and the surface facets leads to a “nested‐octagon” model for the cross sections of AuNRs: shell octagon with high‐index crystalline facets (520), (5‐20), (2‐50), (‐2‐50), (‐5‐20), (‐520), (‐250), and (250), and core octagon consisting of low‐index crystalline facets (100), (1‐10), (0‐10), (‐1‐10), (‐100), (‐110), (010), and (110).

Surface Etching of Polymeric Semiconductor Films Improves Environmental Stability of Transistors

“…A λ 750 K detector was employed to collect the 2D GIWAXS patterns. 59,60 The sample-todetector distance was 115 ± 1 mm, calibrated with cerium dioxide.…”

“…The α i was slightly above the critical angle for total reflection (α c ) of conjugated polymers used in this work but below α c of silicon substrate. A λ 750 K detector was employed to collect the 2D GIWAXS patterns. , The sample-to-detector distance was 115 ± 1 mm, calibrated with cerium dioxide.…”

Effects of Cationic Species in Salts on the Electrical Conductivity of Doped PEDOT:PSS Films

“…the Supporting Information). GIWAXS is a well-established protocol to characterize the surface and interface structures of polymer thin film, , including PEDOT:PSS before and after IL doping. For example, Kee et al demonstrated a highly ordered nanofibrillar structures of PEDOT, and Saxena et al reported a shortened π–π stacking distance between PEDOT molecules upon salts’ doping.…”

Sprayed Nanometer-Thick Hard-Magnetic Coatings with Strong Perpendicular Anisotropy for Data Storage Applications

“…While SEM yields topographical and surface morphology characterization, the strong uniaxial crystallographic anisotropy of the hexaferrite phase (P6 3 /mmc) and single-crystalline nature of the platelets require determining their orientation using diffraction methods, especially for the thicker films. Hence, GIWAXS was employed to quantify the orientations of nanoplatelets in the deposited films 58 (Figures Those distributions differ significantly for NAL and SHF thin films and evolve with the number of layers of hexaferrite particles (Figures 3b,c, S7 and Table S2).…”

“…While SEM yields topographical and surface morphology characterization, the strong uniaxial crystallographic anisotropy of the hexaferrite phase ( P 6 3 / mmc ) and single-crystalline nature of the platelets require determining their orientation using diffraction methods, especially for the thicker films. Hence, GIWAXS was employed to quantify the orientations of nanoplatelets in the deposited films (Figures a and S5). A typical 2D GIWAXS pattern indicates a uniaxial SrFe 12 O 19 texture in the films, with the set of maxima corresponding to the in-plane orientation of the MNPs with the [00l] direction normal to the film surface.…”