Structural and photophysical properties of anthracenyl and carbazolyl groups in silicone-based polymers

• Published in: Journal of luminescence 2012-04, Vol.132 (4), p.972-978
• Main Authors: Domingues, Raquel A., Martins, Tatiana D., Yoshida, Inez V.P., Brasil, Maria J.S.P., Atvars, Teresa D.Z.
• Format: Article
• Language: English
• Subjects: Anthracene; Applied sciences; Carbazole; Electrical, magnetic and optical properties; Exact sciences and technology; Luminescent silicones; Organic polymers; Photophysical properties; Physicochemistry of polymers; Properties and characterization; Siloxanes
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2011.10.027

This paper describes a simple methodology to attach luminescent groups (anthracenyl and carbazolyl) to polysiloxanes (silicone), using hydrosilylation reactions between the Si–H groups from the silicone precursor to vinyl derivatives of the lumophores. The photophysical properties of these luminescent silicones were studied using both steady-state and dynamical photoluminescence spectroscopy. A strong correlation was obtained between the structural characteristics of the anthracenyl- and carbazolyl-based polysiloxanes, depending on the amount and the position of the Si–H bonds in the silicone precursors. For sparsely distributed Si–H groups, both the anthracenyl-labeled and carbazolyl-labeled polysiloxanes showed photophysical properties (fluorescence spectrum and fluorescence decays) similar to those of 1-alkyl anthracenyl and 1-alkyl carbazolyl derivatives, respectively. Nevertheless, for closely spaced Si–H groups, emission and decay are different. The presence of excimers was observed for anthracenyl but not for carbazolyl polysiloxanes. This latter observation is quite different from that observed for carbon-based polymers for which the carbazolyl excimer formation is a very common process probably due to the differences in the silicone structure. The luminescence properties of silicone carbazolyl and silicone–anthracenyl can be controlled by the amount of Si–H groups of the pristine silicone; silicone chain imposes some geometrical restriction to excimer formation. [Display omitted] ► Fluorescent and phosphorescent silicones. ► Structure of the precursor silicone interferes with the emission. ► Excimer emission from anthracenyl groups was obtained for some silicones. ► Excimer emission from carbazolyl groups was not observed for silicones. ► Emission quenching is observed for silicones with high content of lumophores.