Pathways to increase the dissymmetry in the interaction of chiral light and chiral molecules

Abstract

The dissymmetric interaction between circularly polarised (CP) light and chiral molecules is central to a range of areas, from spectroscopy and imaging to next-generation photonic devices. However, the selectivity in...

Elucidating the origin of chiroptical activity in chiral 2D perovskites through nano-confined growth

“…The calculation results support that the asymmetric behavior of hydrogen bonding between the chiral organic molecules and inorganic framework can be amplified depending on the degree of micro-strain, which can promote the efficient chirality transfer process by increasing the chiral distortion in the inorganic framework. These results are consistent with a recent study by Jana et al, which discovered that asymmetric hydrogen-bonding interactions between the chiral spacer cation and lead bromide-based layers cause symmetry-breaking in the inorganic layer 45 . Indeed, asymmetric hydrogen-bonding interaction between the NH 3 + of chiral spacer cations and inorganic layers are crucial for determining the associated electronic structure of chiral 2D OIHPs, thereby giving rise to chiroptical responses, such as CD and CPPL.…”

“…2c ) 34 . If two transition dipole moments are located close enough in space but are not coplanar, the coupling between two exciton transitions generate the splitting of excited states into two levels separated by 2 V 12 , which is referred to as the excited state splitting 45 , 46 . The strength of the interaction can be calculated by the Coulomb dipole–dipole Eq.…”

Frontiers in circularly polarized luminescence: molecular design, self-assembly, nanomaterials, and applications

“…As was discussed above, an increasing number of CPL-active coordination materials, e.g., small-molecular metal complexes, supramolecular assemblies, and MOPs and MOFs, have been prepared. Several strategies have been employed to develop efficient CPL materials, including the utilization of the magnetic dipole-allowed transitions of Ln and Cr(III) complexes, the exploitation of supramolecular chirality based on helical assemblies or chiral liquid crystalline materials, and the exploration of large and supramolecular structures for chirality amplification (e.g., molecular helicates, twisted MOPs, and MOFs [212]. In spite of these advances, the g lum values of most of these reported materials are still low (in the order of 10 −2 or less), and only a few of examples have achieved the value of more than 0.1 for practical optoelectronic applications.…”

An S-shaped double helicene showing both multi-resonance thermally activated delayed fluorescence and circularly polarized luminescence

“…Helicenes are a class of fused polycyclic aromatic frameworks that possess a helically chiral framework, 1,2 where overlapping rings render the enantiomers kinetically stable to racemization. Helicenes usually display strong circular dichroism (CD) 3 and circularly polarized luminescence (CPL), [4][5][6][7][8] which has led them to be investigated in a number of different applications. 4,9 These include nonlinear optics, 10 chemical sensors, 11 asymmetric catalysis, 12,13 circularly polarised luminescent materials [14][15][16] and as ligands in Ir, Zn and Pt complexes, 9 the latter of which have been employed in phosphorescent CP-OLEDs.…”

“…In contrast, organic molecules can attain high absorption and emission intensities but typically show relatively low g PL (r10 À2 ) due to their significantly larger electric transition dipole moments compared to their magnetic transition dipole moments, coupled with their relatively smaller molecular size. 7,8,77,78 Presently, there exists a small number of organic compounds displaying CP-TADF, with most of the reports emerging over the past few years. A number of these have been used in CP-TADF OLEDs, 18,60,62,79,80 showing maximum external quantum efficiencies (EQE max ) surpassing 30% 80 but with g EL typically r10 À3 (Fig.…”