To increase the open circuit voltage (VOC) of polymer solar cells (PSCs) based on polythiophene, two new ester group functionalized polythiophene derivatives, PCTDT and PCTBDT, were designed and synthesized via alternating copolymerization of thiophene‐3‐carboxylate (CT) with the 2,2′‐bithiophene (DT) and benzodithiophene (BDT) units, respectively. The resulting copolymers exhibited broad and strong absorptions in the visible region, which was similar to that of the commonly used poly(3‐hexylthiophene) (P3HT). Through cyclic voltammetry measurements, it was found that both copolymers showed lower HOMO energy levels (−5.27 eV for PCTDT and −5.36 eV for PCTBDT) than that of P3HT (−5.03 eV), indicating that the HOMO energy level could be efficiently reduced by introducing the ester group into the polymer side chain. Photovoltaic properties of the copolymers blended with [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) as electron acceptor were investigated. The obtained two devices possessed both relatively large short circuit current (ISC) and higher VOC than that of P3HT:PCBM blend. For PCTBDT:PCBM blend, a power conversion efficiency (PCE) up to 2.32%, an ISC of 6.94 mA · cm−2, and a VOC of 0.80 V were observed while PCTDT:PCBM system demonstrated a PCE of 1.75% with a VOC of 0.68 V.
Abstract A series of liquid crystalline polyorganosiloxanes containing both azo dye and cholesteryl groups were synthesized by reacting poly[3- chloroformylpropyl)methylsiloxane-co-dimethylsiloxane] with both cholesterol and 4-(4′-methoxyphenylazo)phenol. The yields were between 73 and 81%. Most of these new polyorganosiloxanes are colored solid products. Their chemical structures were confirmed by IR, 1H NMR, and elemental analysis. Their phase behaviors were also investigated by using differential scanning calorimetry (DSC) and polarizing microscopy. The results show that all these polyorganosiloxanes exhibit liquid crystalline behavior at various temperatures and at any azo dye content. As a result of the orientation of both mesogenic azo dye and cholesteryl groups, smectic phases were formed beginning around 0°C, and cholesteric phases appeared above 60°C. 相似文献
A series of spiro compounds with polyfluoroalkyl and phosphonate ester groups has been synthesized via several steps. The structures of these compounds were confirmed by 1H NMR,13C NMR, infrared (IR), and mass spectrometry (MS) as well. The possible reaction mechanism for the formation of these products was also proposed. 相似文献