Printable Deep‐Blue Fluorescent Light‐Emitting π‐Conjugated Polymers for All‐Organic RGB Visible Light Communication

All-organic red-green-blue (RGB) visible light communication (VLC) systems hold significant promise for future wireless communications because they can be readily integrated with existing lighting infrastructures. However, the stability, efficiency, and exciton decay times of printed deep-blue organic light-emitting diodes (OLEDs) currently fall short of the high bandwidth, rapid response, and swift data transmission requirements of VLC systems. Herein, two printable deep-blue fluorescent light-emitting π-conjugated polymers (LπCPs) were fabricated based on a multi-dimensional self-encapsulation strategy for application in all-OLED RGB VLC systems. The printed fluorescent films displayed remarkably fast decay life-times of ∼0.30 ns, enabling high bandwidth and fast response. The deep-blue OLEDs presented a CIE coordinate of (0.15, 0.06), narrow deep-blue emission with a full width at half maximum (FWHM) of 21 nm, high external quantum efficiency (EQE) of 1.94%, and high brightness of 6698 cd/m² with remarkable durability. Finally, preliminary printed all-OLED RGB VLC systems were successfully established, and through efficient energy transfer, demonstrated the transmission of pseudo-random binary sequence (PRBS) signals and audio data at a rate of 1 Mbps. The fast response times, on the order of microseconds, highlight the potential of these all-OLED VLC systems for high-speed data transmission.