Hybrid organic light-emitting device fabricated with semiconducting polyimide via mixed vapor deposition polymerization

Hybrid organic light-emitting devices (HOLEDs) were fabricated with the active molecularly doped polyimide (AMDPI) thin film as a hole-injecting-transporting layer through the mixed vapor deposition polymerization (VDP) process. As a comparison, the polyimide thin film as a hole-injecting-transporting layer was also prepared for a HOLED via VDP. Both the AMDPI and polyimide thin films were almost optically transparent over the entire visible range because the bandgap energy was ∼2.9 eV. HOLEDs with the AMDPI thin film showed a higher luminance and efficiency than that with the polyimide thin film. In particular, the application of a lithium-aluminum cathode significantly enhanced the luminance and the efficiency of HOLEDs with the AMDPI thin film.