Helical Polymer
Working as a Chirality Amplifier to
Generate and Modulate Multicolor Circularly Polarized Luminescence
in Small Molecular Fluorophore/Polymer Composite Films
In-depth studies of chirality and circularly polarized
luminescence
(CPL) have become indispensable in the process of learning human nature.
Small molecules with CPL activity are one of the research hotspots.
However, the CPL properties of such materials are generally not satisfying.
Here, we synthesized a series of chiral small molecular fluorophores
that cannot demonstrate CPL emission themselves. By introducing an
optically inactive helical polymer, chirality transfer and chirality
amplification efficiently occur, thereby generating intense CPL emission.
Through combining different chiralized fluorophores, multicolor CPL-active
films with emission wavelength centered at 463, 525, and 556 nm were
fabricated, with the maximum luminescence dissymmetry factor (glum) being up to −0.028. Then, benefiting
from the strong CPL emission and appropriate energy donor–acceptor
system, we further established a circularly polarized fluorescence-energy
transfer (CPF-ET) strategy in which the CPL-active films work as a
donor emitting circularly polarized fluorescence to excite an achiral
fluorophore (Nile red) as the acceptor, producing red CPL with glum of up to −0.011 at around 605 nm