Conjugated polymers with a stabilized blue emission are of importance for the realization of large flat panel AMOLED displays using polymer light-emitting diodes. Several novel conjugated polymers using newly developed templates for the stabilized EL emission are reported. Poly(2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[def]phenanthrene)) (PCPP) is a new class of blue-emitting polymers utilizing a new back-bone. This material emits a efficient blue EL without exhibiting any unwanted peak in the long wavelength region (green region) even after prolonged annealing at an elevated temperature of 150oC in air, or operation of the device. New electroluminescent spiro-PCPPs, poly((2,6-(3',6'-bis(2-ethylhexyloxy)-spiro(4H-cyclopenta[def] phenanthrene-4,9'-[9H]fluorene)))-alt-(2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[def]phenanthrene))) (spiro-PCPP-alt-PCPP) and poly((2,6-(3',6'-bis(2-ethylhexyloxy)-spiro(4H-cyclopenta[def] phenanthrene-4,9'-[9H]fluorene)))-alt-(1,4-phenylene)) (spiro-PCPPP), have been synthesized by the Suzuki polymerization. The PL emission spectra of polymers in THF solution show a same maximum peak at 397 nm. The maximum PL emission spectra of polymers appeared at around 463 and 456 nm in solid state, respectively. The PL spectra in solid thin films show more red-shifted over 60 nm than solution conditions. The blue emissions at 400-409 nm for the π–π* transitions of conjugated polymer backbone are almost completely quenched or decreased.
Preparation and Chemical Properties of π-Conjugated Polymers Containing Indigo Unit in the Main Chain
