Macroscopic‐Oriented Gold Nanorods in Polyvinyl Alcohol Films for Polarization‐Dependent Multicolor Displays

Abstract

wide range of applications including biomimetic camouflage, [1,2] optical patterning, [3,4] optical data storage, [5,6] display devices, [7,8] electrochromic devices, [9,10] colorimetric sensors, [11,12] and so forth. At present, there are various building blocks to construct the SCNMs, such as photonic crystals, semiconductor nanoparticles, fluorescent molecules, and partial organic photoresponse molecules and their colors are alterable through Bragg diffraction, [13,14] photoluminescence, [15,16] electrochromism, [17,18] and other stimulating means. To date, much effort has been devoted to the fabrication of the SCNMs. Kim and co-workers [19] reported a facile and practical method for the fabrication of highly transparent colloidal photonic crystal films that can show multi ple colors through the overlapping of distinct layers. Rogach and co-workers [20] developed an optical approach to highly align emissive CdSe/CdS core-shell semiconductor nanorods (NRs) and the ordered area can display the color change. Zhu and co-workers [21] reported the design of multicolor fluorescent polymers that shown a color palette from blue to orange under similar excitation conditions. Although these SCNMs can exhibit a variety of colors, it still remains a big challenge to obtain richer colors in a wide spectrum, which impedes their potential applications like full-color electronic paper and electronic device screens.Noble metal nanoparticles are well known for their unique optical properties arising from the surface plasmon resonance (SPR). They usually generate abundant plasmonic colors by precisely modulating the SPR that highly depends on their sizes, morphologies, compositions, and dielectric environment. [22][23][24][25] Compared to other optical colors, the plasmonic color has distinctive optical performance including high color contrast, high resolution, and everlasting colors. [26] More importantly, full colors covering the whole range of the visible light can be obtained by selecting suitable plasmonic materials and nanostructure. For example, Chu and co-workers [2] reported reversible full-color plasmonic cell/display by electrochemically controlling the structure of an gold (Au)-Ag core-shell nanodome array. Kobayashi and co-workers [27] reported a "voltagestep method" to successfully design a multicolor electrochromic device with electrochemically size-controlled Ag nanoparticles.Due to their abundant optical colors, durable color generation, and high refreshing rate, smart chromic nanomaterials (SCNMs) have been employed in various applications. However, most SCNMs often require multicomponent materials, precise morphology control, and complicated modulation to realize multicolor changes, which limits their widely practical applications. In the present study, a simple and effective strategy is demonstrated to achieve the flexible and cost-effective multicolor gold nanorods (Au NRs)/ polymer hybrid film, by tuning macroscopic-oriented Au NRs in films and a synergy of polarization-dependent surface plasmon resonance. ...

Structural Colors by Synergistic Birefringence and Surface Plasmon Resonance

“…At ϕ = 0°, L-SPR is excited with light vibrating along the longitudinal axis of GNRs, whereas light vibrating perpendicular to the longitudinal axis can excite T-SPR at ϕ = 90°. The rotation of the polarizer leads to light absorption at a selected wavelength with tunable intensities due to modified combinations of T-SPR and L-SPR . Because of the aligned GNRs in the hybrid polymer films, the SPR of single GNRs was transferred to CNC/GNR hybrid films in the macroscale by using only one polarizer, without the interference of birefringence from CNCs.…”

“…The rotation of the polarizer leads to light absorption at a selected wavelength with tunable intensities due to modified combinations of T-SPR and L-SPR. 12 Because of the aligned GNRs in the hybrid polymer films, the SPR of single GNRs was transferred to CNC/GNR hybrid films in the macroscale by using only one polarizer, without the interference of birefringence from CNCs. As shown in the UV−vis−NIR spectra of CNCs1/GNRs1 hybrid films measured with one polarizer (Figure 1d), the absorption intensity at a wavelength of 520 nm (T-SPR) largely increased, while that at the wavelength of 1150 nm (L-SPR) greatly decreased with rising ϕ from 0°to 90°.…”

“…Common methods to fabricate structural colors are implemented by constructing periodic nanostructures with distinctly shaped nanoparticles, which can alter the optical field within the subwavelength range to give diverse visible colors. − In this scope, rod-like nanoparticles with distinct optical properties from their inherent anisotropy can be applied to construct optical materials, such as cellulose nanocrystals (CNCs) and gold nanorods (GNRs). − As an example of bio-based anisotropic nanoparticles, CNCs can be integrated into structural color materials due to their optical birefringence. ,, GNRs as the widely applied precious nanoparticles can manipulate the optical field by altering their intriguing anisotropic SPR, which directly leads to visible light absorption. These inherently distinct optical mechanisms allow orthogonal strategies to construct structural color materials through successive interference and interaction with light.…”

Flexible Plasmonic Biosensors for Healthcare Monitoring: Progress and Prospects

“…Lee and co-workers developed pressure sensors based on the mixing and curing of the composite of sea-urchin shaped Au NPs and polyurethane (PU) elastomer (Figure a). Our group achieved uniform Au NP-poly­(vinyl alcohol) (PVA) composite films by curing the mixed Au NPs and PVA precursors. Takei and co-workers obtained highly sensitive electronic whiskers by printing CNTs-Ag NPs in the prepatterned PDMS, thus leading to a flexible biosensor with high strain sensitivity due to the conductive network matrix (Figure b) .…”

Free-Standing 2D Janus Gold Nanoparticles Monolayer Film with Tunable Bifacial Morphologies via the Asymmetric Growth at Air–Liquid Interface

“…The two-dimensional (2D) films of nanoparticles have attracted considerable scientific and technological interest in the past few decades due to their unique optical, magnetic, and electronic properties that distinguish them from their individual nanoparticles and bulk materials. − 2D Au NP monolayer films are widely used in the fields of optoelectronic devices, , sensors, catalysis, oil/water separation, evaporation, and surface enhanced Raman scattering (SERS) spectroscopy, − benefiting from easy fabrication, good chemical stability, and distinct plasmonic properties. , Deng and co-workers developed a reusable evaporation system based on assembled plasmonic gold nanoparticles thin film for high-performance evaporation of seawater. In our previous work, a monolayer film, using light-controlled shrinkage, of gold nanoparticles with excellent free-standing and easily transferable properties was designed and constructed, providing an ideal candidate for SERS applications due to reproducible and high sensitive performance of SERS signals …”