Isoindigo-Containing Molecular Semiconductors: Effect of Backbone Extension on Molecular Organization and Organic Solar Cell Performance

详细信息    查看全文

• 作者：Yi Ren ; Anna K. Hailey ; Anna M. Hiszpanski ; Yueh-Lin Loo
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：November 25, 2014
• 年：2014
• 卷：26
• 期：22
• 页码：6570-6577
• 全文大小：400K
• ISSN：1520-5002

文摘

We have synthesized three new isoindigo-based small molecules by extending the conjugated length through the incorporation of octyl-thiophene units between the isoindigo core and benzothiophene terminal units. Both UV鈥搗is and Grazing incidence X-ray diffraction experiments show that such extension of the 蟺-conjugated backbone can induce H-aggregation, and enhance crystallinity and molecular ordering of these isoindigo-based small molecules in the solid state. Compared to two other isoindigo-based derivatives in the series, the derivative with two octyl-thiophene units, BT-T2-ID, is the most crystalline and ordered, and its molecular packing motif appears to be substantially different. Devices utilizing these new extended isoindigo-based small molecules as the electron donor exhibit higher performance than those utilizing nonextended BT-ID as the electron donor. Particularly, devices containing BT-T2-ID in an as-cast blend with PC₆₁BM show power conversion efficiencies up to 3.4%, which is comparable to the best devices containing isoindigo-based molecular semiconductors and is a record among devices containing isoindigo-based small molecules that were processed in the absence of any additives.