Synthesis of Poly(N‐aryl‐2,7‐carbazole)s for Efficient Blue Electroluminescence Materials

Several poly(N-phenyl-2,7-carbazole)s that have dialkoxy groups at the m- and p-positions (PmpCzDC, PmpPhDC, PmpCBiDC, PmpEHC), a silyl group at the p-position (PpPhDSiC), and a diphenylamino group (PmPhDAC, PmEHAC) at the m-position of the N-phenyl portion are synthesized, and their optical properties are characterized. These polymers have been used as emitting layer materials of organic light-emitting diode (OLED) devices that have a configuration of ITO/PEDOT(PSS)/polymer/CsF/Al. The OLED devices embedded with PmpCzDC, PmpPhDC, and PmpEHC show intense luminance of about 15 000 cd · m−2 with efficiencies of about 1 cd · A−1, while the devices embedded with PpPhDSiC, PmPhDAC, and PmEHAC show less luminance but retain the color purity of blue emission under a wide range of applied voltages.