Various conjugated polymers self-assemble to form well-defined microspheres that act as optical resonators. Upon focused laser irradiation, the single isolated microspheres exhibit whispering gallery mode photoluminescence (PL), where sharp and periodic emission lines appear in the PL spectra. Efficient and long-range intersphere light energy transfer is demonstrated using coupled microspheres. Conjugated polymer microspheres are advantageous as optical resonators in terms of their high refractive index, photoabsorptivity, and PL efficiency, as well as simple and low-energy fabrication processes, beneficial for the practical application.
