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

Abstract

Abstract Several poly( N ‐phenyl‐2,7‐carbazole)s that have dialkoxy groups at the m ‐ and p ‐positions (P mp CzDC, P mp PhDC, P mp CBiDC, P mp EHC), a silyl group at the p ‐position (P p PhDSiC), and a diphenylamino group (P m PhDAC, P m EHAC) 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 P mp CzDC, P mp PhDC, and P mp EHC show intense luminance of about 15 000 cd · m −2 with efficiencies of about 1 cd · A −1 , while the devices embedded with P p PhDSiC, P m PhDAC, and P m EHAC show less luminance but retain the color purity of blue emission under a wide range of applied voltages. magnified image