Synthesis and light-emitting properties of copolymers composed of fluorene and N-alkoxyphenylphenothiazine

• Published in: Synthetic metals 2009-08, Vol.159 (15), p.1672-1676
• Main Authors: Kim, Suk-Kyung, Eom, Jae-Hoon, Mi, Dongbo, Jung, Choong-Hwa, Lee, Ji-Hoon, Kang, In-Nam, Kim, Jae-Hoon, Hwang, Do-Hoon
• Format: Article
• Language: English
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Light-emitting diodes; N-Alkoxyphenylphenothiazine; Optoelectronic devices; Organic polymers; Organic semiconductor; Physicochemistry of polymers; Polyfluorene; Polymers with particular properties; Preparation, kinetics, thermodynamics, mechanism and catalysts; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/j.synthmet.2009.05.005

Poly[10-(4′-octyloxyphenyl)-phenothiazine-3,7-diyl] (POPPTZ), poly[9,9-bis(4′-octyloxyphenyl)fluorene-2,7-diyl] (PBOPF), and their random copolymers, poly(BOPF- co-OPPTZ), were synthesized through Ni(0) mediated polymerization. Light-emitting devices were fabricated using these polymers in an ITO (indium-tin oxide)/PEDOT:PSS/polymer/Ca/Al configuration. Each EL device constructed with a poly(BOPF- co-OPPTZ) copolymer exhibited significantly enhanced efficiency and brightness compared to devices constructed from the POPPTZ and PBOPF homopolymers. The EL device constructed with poly(83BOPF- co-17OPPTZ) exhibited the highest power efficiency and brightness (8,610 cd/m 2 and 2.831 cd/A, respectively). This enhanced efficiency of the copolymer devices results from their improved hole injection and more efficient charge carrier balance, which arise due to the HOMO levels (∼5.42 eV) of the poly(BOPF- co-OPPTZ) copolymers, which are lower than that of the PBOPF homopolymer (∼5.79 eV).