Structural, Thermo-Optical, and Photophysical Properties of Highly Oriented Thin Films of Quinoxalinophenanthrophenazine Derivative

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• 作者：Tomasz Makowski ; Rasha M. Moustafa ; Pawel Uznanski ; Wojciech Zajaczkowski ; Wojciech Pisula ; Adam Tracz ; Bilal R. Kaafarani
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：August 14, 2014
• 年：2014
• 卷：118
• 期：32
• 页码：18736-18745
• 全文大小：546K
• ISSN：1932-7455

文摘

The structural, thermo-optical, and anisotropic photophysical properties of highly oriented thin solid films of 2,11-bis(1,1-dimethylethyl)-6,7,15,16-tetrakis(dodecyloxy)quinoxalino[2鈥?3鈥?9,10]phenanthro[4,5-abc]phenazine (TQPP-OC₁₂) prepared by a zone-casting method are discussed. The films were obtained on glass substrate by solution processing. The in-plane alignment of TQPP-OC₁₂ molecules in the formed layers was studied by X-ray diffraction methods, optical polarized microscopy combined with thermo-optical analysis, atomic force microscopy (AFM), and UV鈥搗is absorption and fluorescence spectroscopy both with polarized light methods. The high molecular order of zone-casted TQPP-OC₁₂ was studied in conjunction with the observed abundance of phase transitions as a function of thermal conditions to assess the material鈥檚 suitability for optoelectronic device applications. The molecular disk planes in the as-cast samples are parallel to the casting direction and orient almost perpendicularly (96掳) to the substrate. Continuous films with a thickness of 200鈥?00 nm are formed from lamellas arranged parallel to the surface. All observed phase transitions have crystal鈥揷rystal character; however, molecular primary arrangement remains basically identical for all processing conditions. Sample annealing destroys the multiple polymorphs observed in the as-cast sample and leads to an increase of molecular ordering.