Di-aryl substituted poly(cyclopenta[def]phenanthrene) derivatives containing carbazole and triphenylamine units in the main chain for organic light-emitting diodes

The syntheses and characterization of poly(2,6-(4,4-bis(4-((2-ethylhexyl)oxy)phenyl)-4H-cyclopenta[def] phenanthrene)-alt-triphenylamine-4,4′-diyl) (TPA-PCPP), poly(2,6-(4,4-bis(4-((2-ethylhexyl)oxy)phenyl)-4H-cyclopenta [def]phenanthrene)-alt-3,6-(9-(2-ethylhexyl)carbazole)) (3,6-Cz-PCPP), poly(2,6-(4,4-bis(4-((2-ethylhexyl)oxy)-phenyl)-4H-cyclopenta[def]phenanthrene)-alt-2,7-(9-(2-ethylhexyl)carbazole)) (2,7-Cz-PCPP), and poly(2,6-(4,4-bis(4-((2-ethylhexyl)oxy)phenyl)-4H-cyclopenta[def]phenanthrene)-co-2,7-(9-(2-ethylhexyl)carbazole)) (2,7-Cz-co-PCPP) are presented. The carbazole and TPA moieties, which can influence the highest occupied molecular orbital (HOMO) energy level, were introduced to the di-aryl substituted PCPP backbone. The PL spectra of the polymer films showed maximum peaks at approximately 417–429 nm. The devices of the 2,7-Cz-co-PCPPs with the configurations of ITO/PEDOT:PSS/polymers/Ca/Al generated EL emissions with maximum peaks at approximately 460 nm, CIE coordinates of (x =0.16, y=0.033−0.038), turn-on voltages of 4–5 V, maximum brightness of 309-337 cd/m2, and luminescence efficiencies of 0.06–0.09 cd/A. The synthesized polymers may be useful for PLED device applications. [inline-graphic not available: see fulltext]