Highly efficient room temperature phosphorescent liquid crystalline polymer optical waveguides for advanced optoelectronics

Active organic optical waveguide materials (OOWMs) incorporating room temperature phosphorescence (RTP) hold significant promise for diverse applications in photonic and optoelectronic devices. Despite this potential, realizing active RTP optical waveguides with large-sized ordered structures and minimal light loss remains a formidable challenge. To address this issue, we present a groundbreaking thermoplastic active OOWM with low light loss, leveraging room temperature phosphorescent liquid crystalline polymer (LCP). This innovative material can be easily synthesized through the copolymerization of phosphorescent and liquid crystalline monomers. The resulting RTP copolymer exhibits a nematic liquid crystal phase with a phosphorescence lifetime of approximately 0.15 ms and an afterglow duration of around 1 second. Leveraging the excellent processability of LCP, we successfully produce meter-scale fibers via melt spinning. These RTP LCP fibers, characterized by a high orientation of mesogens along the fiber axis, demonstrate superior light confinement and efficient light conduction compared to unoriented samples, resulting in a low optical loss coefficient of 0.13 dB/mm. Furthermore, the thermal responsiveness of the RTP LCP optical waveguide enables its use as a photo switch. This pioneering work paves the way for the design of new OOWMs tailored for advanced photonics and optoelectronics devices.