Synthesis of fluorescent conjugated polymer nanoparticles and their immobilization on a substrate for white light emission

Fluorescent conjugated polymers (CPs) for blue, green, and red emission were polymerized via the Suzuki coupling reaction. Their chemical structures were based on a phenylene unit in the backbone and thus could be excited at the same wavelength to fluoresce their own emission colors. The resultant polymers were fabricated into conjugated polymer dots (CPdots), maintaining their emission colors of red, green, and blue. The CPdots were immobilized on electrospun nanofibers or glass slides to fabricate white-light-emitting materials under single-wavelength excitation. The immobilization on the substrate could effectively avoid the unnecessary energy transfer from a short to a long wavelength emission, which has been known to be an obstacle for white emission when using mixed colors. White light emission (WLE) was successfully attained using spatially separated CPdots located on the nanofibers and on the glass. WLE upon excitation of a blue light-emitting diode (LED) lamp was demonstrated, pointing to a potential application for flexible white illumination.