A Single‐Enantiomer Emitter Enabled Superstructural Helix Inversion for Upconverting and Downshifting Luminescence with Bidirectional Circular Polarization

Abstract

The helical twisting tendency of liquid crystals (LCs) is generally governed by the inherent configuration of the chiral emitter. Here, we introduce the multistage inversion of supramolecular chirality as well as circularly polarized luminescence (CPL) by manipulating the ratio of single enantiomeric emitters (R‐PCP) to LC monomers (5CB). Increasing the content of R‐PCP from 1 wt % to 3 wt % inverted the helix of LCs from left‐handed to right‐handed, accompanying a CPL sign changed from positive to negative. The biaxiality of chiral emitters, as well as the steric effect of chiral‐chiral and chiral‐achiral interaction, were identified as the reasons for helical sense inversion. Due to the strong helical twisting power, 4 wt % R‐PCP drove the photonic band gap (PBG) of chiral LCs to match up with their emission range, leading to an inversion of the CPL again with a high dissymmetry factor (≈1.2). Directly adjusting the PBG using chiral emitters is seldom achieved in cholesteric LCs. On this basis, an achiral sensitizer PtTPBP was assembled into the helical superstructure. The generation of triplet‐triplet annihilation‐induced upconverted CPL from R‐PCP and the downshifting CPL from PtTPBP with opposite rotation was achieved in a single chiral LC system by tuning the position of the PBG.

Dynamic Circularly Polarized Luminescence Switching of Metal–Organic Supramolecular Polymers Directed by the Competition of Solvent-Assisted Nucleation and Thermal Nucleation

“…Supramolecular polymers have become a kind of promising smart nanomaterials for fabricating nanoarchitectures with tunable dimensions and chirality in optoelectronic displays, spin devices, information processing, and biomedical engineering. − Unlike conventional covalent polymers, supramolecular polymers are driven by reversible noncovalent interactions such as hydrogen bonding, − π–π stacking, metal–ligand coordination, and metallophilic interaction, , possessing the intrinsically dynamic property for the establishment of various stimulus-responsive soft materials. − Metal–organic supramolecular polymers (MOSPs), mainly driven by the metal–ligand coordination, metal–π interaction, and metallophilic interaction, collectively endow the variable coordinated sites and tunable conformations of metal complexes, making it easy to modulate the dynamic chirality transfer and morphology transitions of aggregates and nanostructures. Recently, the focus of research on MOSPs has shifted to the supramolecular systems with a kinetically controlled self-assembly process, which provides a variety of regulation methods for supramolecular chirality and morphology. − Out-of-equilibrium self-assembly, consecutive or competitive assembly, living supramolecular polymerization, polymorphism, and dissipative self-assembly are all developed on this basis.…”

Inverted and Amplified Circularly Polarized Luminescence Behavior Originated from Structure–Activity Regulation of Achiral Pyrene-Based Polymers in Chiral Coassemblies

“…Circularly polarized luminescence (CPL) materials have received significant attention in recent years due to their potential applications in optical devices and optical information encryption. − A critical parameter for evaluating the performance of CPL materials is the luminescence dissymmetry factor ( g lum ). − It is defined as g lum = 2 × ( I L – I R )/( I L + I R ) where I L and I R denote the intensities of left- and right-handed circularly polarized light, respectively . Theoretically, the g lum value ranges from −2 to +2 where −2 represents purely right-handed CPL and +2 represents purely left-handed CPL .…”

Ligand engineering of circularly polarized luminescence inversion and enhancement for chiral Ag6 nanoclusters

“…Recently, nanomaterials with excellent circularly polarized luminescence (CPL) have attracted much attention due to their fascinating chiroptical performances and great potential for application in advanced information processing, chiral optoelectronic devices, and chiral biosensing. 17–29 An ideal CPL-active material usually needs to have both high photoluminescence quantum yield (QY) and large luminescence asymmetry factor ( g lum ). 30,31 Thus, chiral nanoclusters became an excellent candidate for constructing CPL-active materials with both high QY and tuneable supramolecular chirality.…”