Solution processable donor–acceptor oligothiophenes for bulk-heterojunction solar cells
作者:Weifeng Zhang、Shing Chi Tse、Jianping Lu、Ye Tao、Man Shing Wong
DOI:10.1039/b926203b
日期:——
Novel p-type and low bandgap penta- and hexa-thiophenes asymmetrically endcapped with solubilizing triarylamine or triarylamino-substituted carbazole dendron and dicyanovinyl groups, namely, PhNOF-OT(n)-DCN and G2-OT(n)-DCN, respectively where n = 5â6 for solution-processable photovoltaic applications have been synthesized and investigated. With the incorporation of a solubilizing electron-donating group, the highly extended oligothiophenes are highly soluble in common organic solvents and solution-processable. Upon extending the oligothiophene backbone, there is a strong increase in the absorption around 420 nm in addition to the intramolecular charge-transfer absorption (520 nm) which results in a strong spectral broadening. The optical band-gap of these donorâacceptor oligothiophene thin-films greatly reduces to 1.85 eV. The solution-processed bulk heterojunction PV cells fabricated from these materials blended with PCBM as an acceptor showed a PCE up to 1.72% with Voc = 0.79 V in an as-fabricated device. Our findings also suggest that highly extended donorâacceptor oligomers can be useful for a p-type, low-bandgap semiconductor for solution-processable bulk heterojunction PV cells.
我们合成并研究了新型 p 型和低带隙五噻吩和六噻吩,它们不对称地端封有增溶三芳基胺或三芳基氨基取代的咔唑树枝基和二氰基乙烯基,即 PhNOF-OT(n)-DCN 和 G2-OT(n)-DCN(其中 n = 5â6 ),分别用于可溶液加工的光伏应用。由于加入了增溶电子供体基团,高度延伸的低聚噻吩在普通有机溶剂中的溶解度很高,并且可以溶液加工。延伸低聚噻吩骨架后,除了分子内电荷转移吸收(520 nm)外,420 nm 附近的吸收也会强烈增加,从而导致强烈的光谱展宽。这些供体-受体低聚噻吩薄膜的光带隙大大降低至 1.85 eV。由这些材料与 PCBM 作为受体混合制成的溶液加工体异质结光伏电池显示出高达 1.72% 的 PCE,在原器件中的 Voc = 0.79 V。我们的研究结果还表明,高度扩展的供体-受体低聚物可用作可溶液加工的体异质结光伏电池的 p 型、低带隙半导体。