Circularly Polarized Luminescent Chiral Photonic Films Based on the Coassembly of Cellulose Nanocrystals and Gold Nanoclusters

Abstract

In this work, we studied the formation and properties of composite films coassembled by cellulose nanocrystals (CNCs) and bovine serum albumin-stabilized gold nanoclusters (BSA-AuNCs). The influences of the BSA-AuNC concentration on the structure and optical properties of CNC-based composite films were further studied. It was found that the composite film retained the chiral nematic structure and optical activity. The self-assembled CNC and BSA-AuNC helical superstructures can produce strong, left-handed, circularly polarized luminescence with dissymmetry factors up to 0.287. Meanwhile, the third component, polyethylene glycol, was introduced without affecting the structural color and fluorescence characteristics of the composite film to enhance the flexibility of the film. The simplicity of the film preparation, the abundance of CNCs, and the flexibility and stability of the composite films pave the way for the production of functional materials with integrated functions.

Circularly Polarized Luminescence from Atomically Precise Gold Nanoclusters Helically Assembled by Liquid‐Crystal Template

“…However, template‐driven helical assemblies present significant increase of g lum values, e.g., in case of bimetallic nanoclusters, [ 34 ] g lum was on the order of 10 −2 and our results yield g lum values comparable to luminescence dissymmetry factors of helical superstructures such as chiral photonic cellulose gold nanocluster films reported by Zhang et al. [ 35 ]…”

“…They are two orders of magnitude higher than commonly reported values for single gold nanoclusters [32] and their aggregates, [33] which are within 10 −3 range. However, template-driven helical assemblies present significant increase of g lum values, e.g., in case of bimetallic nanoclusters, [34] g lum was on the order of 10 −2 and our results yield g lum values comparable to luminescence dissymmetry factors of helical superstructures such as chiral photonic cellulose gold nanocluster films reported by Zhang et al [35] In order to prove that observed CPL originates from the luminescence of helically assembled gold nanoclusters, we have measured the luminescence spectra (Figure S8, Supporting Information) from the map locations showing the strongest opposite g lum . Observed emission bands were broader and significantly weaker than the ones collected in bulk measurements (Figure 3b), but they still show recognizable peak of nanoclusters emission around 880 nm.…”

Synthesis of the Red-Emitting (Ba, Ca)2ScAlO5:Eu3+ Phosphors with Photoluminescence Properties

“…The multi-excitation peaks from 360 to 465 nm can be assigned to the absorption of ground state energy level 7 F 0 to excited state energy level 5 D 2 , 5 D 3 , 5 L 6 , 5 L 7 , or 5 D 4 belonging to the 4f–4f transition of Eu 3+ ion. , In a nutshell, the multiple optimal excitation wavelengths (λ ex = 255–465 nm) were obtained according to EEM. However, there is a large amount of Rayleigh scattering in the EEM results. , The Rayleigh scattering makes the actual intensity of peaks in phosphors masked, especially in the lower λ ex , resulting in indistinguishable peak intensities. To further determine the optimal excitation wavelength, we selected the λ ex = 255–465 nm to obtain the PL spectra with the elimination of Rayleigh scattering.…”

Biomolecule‐Based Circularly Polarized Luminescent Materials: Construction, Progress, and Applications

“…Chiral photonic films exhibit dual CPL and circularly polarized room‐temperature phosphorescence (Figure 7c) [132] . Zhang and co‐workers studied the formation and properties of composite films co‐assembled from CNCs and bovine serum albumin‐stabilized gold nanoclusters; among them, AuNCs using BSA as a template had the advantages of simple preparation, red emission, and high quantum yield [133] . In addition, researchers have also prepared upconversion nanostructure photonic cellulose films from CNCs and PVA‐stabilized NPs [134] .…”