Robust angular anisotropy of circularly polarized luminescence from chiral π-conjugated polymer microspheres with twisted bipolar configuration

Here we show that conjugated polymers bearing chiral side chains self-assemble into solid microspheres with a twisted bipolar interior. The resultant microspheres, when dispersed in methanol, exhibit CPL with a glum value as high as 0.23. The microspheres are mechanically robust enough to be handled with a microneedle under ambient conditions, allowing comprehensive examination of the angular anisotropy of CPL. The single microsphere is found to exhibit distinct angularly anisotropic birefringence and CPL with glum up to ∼0.5 in the equatorial plane, which is 2.5-fold greater than that along the polar axis. Such optically anisotropic solid materials are important for the application to micrometer-scale light-emitting, visualizing, and optical vortex generation devices.