| Summary: | 碩士 === 國立中興大學 === 化學工程學系所 === 99 === A new series of low-band gap of P-type conjugated polymers containing pendant triphenylamines and carbazole were synthesized via Stille coupling reactions. The introduction of 2-ethylhexyl groups as side chains increased the polymer solubility and high molecular weight. All polymers exhibited good solubility in common organic solvents, and stable thermal properties. Moreover, further introduction of triphenylamines and carbazoles as side chains would broaden the absorption of solar spectra and modulate the HOMO levels of polymers, and resulted in much better oxidative stability. We were able to lower HOMO levels and increased the polymer open circuit voltage (Voc). Consequently, a larger open circuit voltage was acquired.
Due to the fact that the incorporation of unsubstituted conjugated moieties in the polymer backbones could provide sufficient free volume, much better miscibility of bulk heterojunction was observed. All polymers exhibited good miscibility with PC61BM, which provided more chances for exciton dissociation. Thus a higher short-circuit current ( Jsc ) was obtained.
The best performance was achieved in the following : a power conversion efficiency of 1.94 % and a Voc of 0.69 V, Jsc 8.78 mA/cm2 under illumination of AM 1.5, 100 mW/cm2. This finding suggests that the polythiophene derivative comprising pendants bulky steric groups as side chains are potentially useful for solar cell applications.
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