Date

2016

Author

Atakan, Gizem

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For potential application of electrochromic materials in display technologies, materials having additive or subtractive primary colors in their neutral states that switch to a highly tranmissive states are desired since the entire color spectrum can be created using these materials. The RGB color model requires three complementary colors; red, green and blue. Even though the RGB colored polymers in the electrochromic research area were fulfilled over the past decade, towards high quality display applications, electrochromic materials with better optical contrasts and faster switching times are needed. As a result, realization of novel electrochromic materials is still a major aim in the field. Additionally, a well-defined neutral state red polymeric materials appear to be absent in the literature. Donor-acceptor type polymers generally result in two absorption bands. But for the red to transmissive polymeric materials, single absorption band is needed. Therefore, based on the previous observations in the field, the key approach for the synthesis of well-defined novel red to transmissive polymeric materials was appeared to be the coupling of units that are known to polymerize to give superior electrochromic properties, with highly conjugated donor materials. Under the light of this approach, a monomer which consists of EDOT and phenanthrocarbazole units was designed and polymerized electrochemically. Its electrochromic properties were investigated in detail. The polymer showed the well promised red to transmissive color change with a high optical contrast value of 51% and fast switching times of 0.65 s for oxidation and 0.52 s for reduction. Additionally, towards realization of a solution processable derivative, a novel monomer with ProDOT unit that contains alkyl chains and phenanthrocarbazole was successfully synthesized. The corresponding polymer was synthesized both by electrochemical and chemical methods. Unlike its EDOT containing analogue, the polymer switches between orange and transmissive grey color with a green intermediate with high optical contrast values of 58% for the electrochemically synthesized and 60% for chemically synthesized polymer. The materials showed fast switching times of 1.3 s and 0.9 s respectively. Additionally, the polymer showed strong orange luminescence in its neutral state which completely diminishes upon oxidation. Hence polymer is one of the rare examples of a semiconducting polymer that shows both color and luminescence change upon applied potential.

Subject Keywords

Optoelectronics., Electrochromism., Electrochemistry., Conjugated polymers.

URI

http://etd.lib.metu.edu.tr/upload/12620295/index.pdf
https://hdl.handle.net/11511/25855

Collections

Graduate School of Natural and Applied Sciences, Thesis