Stable green light-emission from poly[9,9-bis(4-n-octyloxyphenyl)fluorenyl-2,7-vinylene] synthesized via the Gilch polymerization route

Abstract

A new fluorene-containing poly(arylenevinylene) derivative, poly[9,9-bis(4-octyloxyphenyl)fluorenyl-2,7-vinylene] (PBOPFV), was synthesized via the Gilch polymerization route and its light-emission properties were characterized and compared with those of poly(9,9-di-n-octylfluorenyl-2,7-vinylene) (PFV). As is the case for poly(alkylfluorene)s, PFV exhibits a long-wavelength emission that is additional to its emission in the blue-green region after thermal annealing or the passage of current. We have successfully suppressed this long-wavelength emission by introducing an octyloxyphenyl group at the 9-position of the fluorene group. PBOPFV produces PL emission maxima at 478 and 510 nm and no significant changes were found in its PL emission spectrum even after thermal annealing at 150 C for 2 h. Light-emitting devices were fabricated with ITO/PEDOT:PSS/polymer/LiF/Al configurations. The EL spectrum of the device constructed using PFV was found to undergo significant changes during device operation, whereas the EL spectrum of the device constructed using PBOPFV was found to be stable.