Low-Bandgap Small-Molecule Donor Material Containing Thieno[3,4-b]thiophene Moiety for High-Performance Solar Cells

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• 作者：Feng Liu ; Haijun Fan ; Zhiguo Zhang ; Xiaozhang Zhu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：February 17, 2016
• 年：2016
• 卷：8
• 期：6
• 页码：3661-3668
• 全文大小：484K
• ISSN：1944-8252

文摘

By replacing the central thiophene of STDR, a sepithiophene terminated with two 3-ethylrhodanine moieties, with 2-ethylhexyl 3-fluorothieno[3,4-b]thiophene-2-carboxylate, an A–D–Q–D–A-type small molecule has been developed for high-performance organic solar cells with improved photocurrent. STDR-TbT exhibits a significant bathochromic shift with a low optical bandgap of approximately 1.60 eV in the thin film. Accordingly, STDR-TbT shows broad external quantum efficiency spectral response up to 800 nm. A high short circuit current (J_sc) of 10.90 mA cm^–2 was achieved for STDR-TbT:PC₇₁BM-based devices; this is significantly higher than that of STDR:PC₇₁BM-based devices, J_sc: 5.61 mA cm^–2, with a power-conversion efficiency (PCE) of 5.05%. Compared with STDR-based devices, STDR-TbT-based devices show balanced charge carrier transport, better thin-film morphology, and favorable charge separation/collection.