- Peripheral Substitution of Tetraphenyl Porphyrins: Fine-Tuning Self-Assembly for Enhanced Electroluminescence
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This study reports the synthesis of two novel zinc porphyrin families bearing four or eight alkoxy chains at their peripheral phenyl rings, with the length of the alkoxy chains ranging from 2, to 6, and to 12 carbon atoms. All zinc porphyrin derivatives were fully characterized with respect to their photophysical and electrochemical features. The zinc porphyrins could be processed into thin films which, depending on the length of the alkoxy chains on the aryl substituents, were found to be either of an ordered or a disordered nature, as it is revealed by spectroscopic and microscopic techniques. The films containing ordered self-assemblies displayed significantly enhanced electrical conductivity compared to the disordered films. This led to remarkable differences regarding their electroluminescence response that occurs at lower bias. Furthermore, their luminous efficiency was of almost one order of magnitude higher than that of disordered films.
- Charisiadis, Asterios,Bagaki, Anthi,Fresta, Elisa,Weber, Katharina T.,Charalambidis, Georgios,Stangel, Christina,Hatzidimitriou, Antonios G.,Angaridis, Panagiotis A.,Coutsolelos, Athanassios G.,Costa, Rubén D.
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p. 254 - 265
(2018/04/24)
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- Observation of co-existence of 'face-on' and 'edge-on' stacking styles in a porphyrin monolayer
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We report a direct observation adopting 'face-on' and 'edge-on' stacking styles in monolayer of a novel porphyrin derivative on highly ordered pyrolytic graphite (HOPG) using scanning tunneling microscope (STM). The porphyrin derivative, 5-hydroxyphenyl-10, 15, 20-trikis(4-dodecyloxyphenyl) porphyrinatozinc(II) (ZnDPPOH) is synthesized and assembled on HOPG. In the STM images, we observed two kinds of ordered domains. One consists of ZnDPPOH dimmers, adopting 'face-on' stacking style, the other exhibits a segmented columnar structure, like piled-up 'armchairs', lying down on the substrate, adopting an 'edge-on' stacking style. In the latter case, the conjugated and highly delocalized π-systems play key roles in stabilizing the monolayer.
- Zhou, Yunshen,Wang, Bing,Zhu, Manzhou,Hou
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p. 140 - 145
(2007/10/03)
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