The influence of keto defects on photoexcitation dynamics in polyfluorene

• Published in: Synthetic metals Vol. 139; no. 3; pp. 851 - 854
• Main Authors: Romaner, L., Piok, T., Gadermaier, C., Guentner, R., Scandiucci de Freitas, P., Scherf, U., Cerullo, G., Lanzani, G., List, E.J.W.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 09-10-2003; Amsterdam Elsevier Science; New York, NY
• Subjects: Applied sciences; Electrical, magnetic and optical properties; Exact sciences and technology; Femtosecond spectroscopy; Keto defect; Organic polymers; Photo-induced absorption; Physicochemistry of polymers; Polyfluorene; Properties and characterization; Photo-induced absorption; Femtosecond spectroscopy; Polyfluorene; Keto defect; Substituent effect; Polaron; Arylene copolymer; Fluorene derivative polymer; Experimental study; Arylene polymer; Conjugated polymer; Conjugated copolymer; Photoexcitation
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/S0379-6779(03)00259-5

The optical properties of two differently substituted types of polyfluorenes, 9-monoalkylated PF (mono-PF) and 9,9-dialkylated PF (bi-PF) where studied by means of photo-induced absorption (PIA) and ultrafast pump and probe measurements. The photo-induced absorption was complemented by measurements on a fluorene–fluorenone copolymer, which can be seen as a model substance for the polyfluorenes containing keto-defect sites. By differential transmission measurements we show that for the 9-monoalkylated PF measurements the singlet and triplet signal is strongly reduced compared to the 9,9-dialkylated PF. Instead, the polaron signal becomes the dominant feature.