Chirality Induction to CdSe Nanocrystals Self-Organized on Silica Nanohelices: Tuning Chiroptical Properties

Abstract

CdSe nanocrystals (NCs) were grafted on chiral silica nanoribbons, and the mechanism of resulting chirality induction was investigated. Because of their chiral organization, these NCs show optically active properties that depend strongly on their grafting densities and sizes of the NCs. The effect of the morphology of the chiral silica templates between helical (cylindrical curvature) vs twisted (saddle like curvature) ribbons was investigated. The g-factor of NCs-silica helical ribbons is larger than that of the NCs-silica twisted ribbons. Finally, rod-like NCs (QR) with different lengths were grafted on the twisted silica ribbons. Interestingly, their grafting direction with respect to the helix surface changed from side-grafting for short QR to tip-grafting for long rods and the corresponding CD spectra switched signs.

Liquid Crystal Templated Chiral Plasmonic Films with Dynamic Tunability and Moldability

“…This phenomenon was previously reported for semiconductor nanorods. [ 67 ] A few different lengths of helical assemblies of Au15 were tested to verify if this parameter changes the characteristics of PCD signals (Figure 4g). Modeled spectra exhibited the Cotton effect with signs and positions of the bands perfectly matching the experimental results.…”

Active Regulation of Supramolecular Chirality through Integration of CdSe/CdS Nanorods for Strong and Tunable Circular Polarized Luminescence

“…Imparting chirality into inorganic nanoparticles to build up chiral nanomaterials will potentially reshape the application scope of traditional inorganic materials, including chiral separation, asymmetric catalysis, enantioselective sensing, and optoelectronics. − Three distinct approaches have been discovered to render inorganic nanomaterials chiral, including (i) nanoparticles with intrinsic chirality from crystalline defects, , (ii) chiral interactions between chiral surface ligands and nanoparticles, − and (iii) chiral assembly of nanoparticles via chiral templating. − Among these approaches, chiral assembly enabled by chiral templating is intriguing, and diverse chiral templates, ranging from DNA, peptides, and natural virus to liquid crystals and organogelators, have been explored to engineer chiral nanoparticle assemblies. − Among the diverse inorganic nanoparticles, colloidal semiconductor nanoparticles (also called quantum dots) with size-dependent optical properties and high photoluminescence quantum yields (PLQYs) were intensively studied as chiral emitters when chiral infomation was input into the nanoparticles or their assemblies. , Liu and co-workers have applied a chiral gelator to assist the assembly of achiral CdSe@ZnS quantum dots into chiral emitters with a dissymmetry factor of the circularly polarized luminescence (CPL) signal of ∼10 –3 . Recently, Oda and co-workers have applied chiral silica nanoribbons as chiral templates to induce the chiral assembly of CdSe quantum dots into helical assemblies . Up to date, the chiral information on these nanoparticle assemblies is usually inherited from the templating materials.…”

“…26 Recently, Oda and co-workers have applied chiral silica nanoribbons as chiral templates to induce the chiral assembly of CdSe quantum dots into helical assemblies. 27 Up to date, the chiral information on these nanoparticle assemblies is usually inherited from the templating materials. In other words, these inorganic nanoparticles are passive elements and usually considered as "particulate dyes", implementing the assemblies with intriguing chiroptical properties.…”

Disentangling Excimer Emission from Chiral Induction in Nanoscale Helical Silica Scaffolds Bearing Achiral Chromophores

“…Particularly for this latter reason, as noted previously, it is important to take into account the grafting density of the dyes when comparing ICD and excimer emission [12] . The grafting density of the dyes was calculated and is summarized in Table 2 for both right‐ and left‐handed silica helical or twisted ribbons [29] …”

“…[12] The grafting density of the dyes was calculated and is summarized in Table 2 for both right-and left-handed silica helical or twisted ribbons. [29] The results show that the ortho-substituted benzamides have much lower surface coverage than the corresponding meta-or para-derivatives. This can be understood on the basis of steric interactions that constrain the geometry of the benzamide linker to be perpendicular to the plane of the aromatic chromophore.…”