作者:Charles M. Shaw、Xinnan Zhang、Lidaris San Miguel、Adam J. Matzger、David C. Martin
DOI:10.1039/c3tc30144c
日期:——
Recent progress in thienoacene development has produced numerous high performance, air-stable organic semiconductor materials. Pentathienoacene (T5) thin film devices have shown poor performance despite promising computational studies, likely due to high mobility anisotropy and poor film morphology. 2,6-Bis-alkyl-pentathienoacene has been synthesized to enable solution-processing routes to better microstructures of T5-based devices. Soluble side groups are introduced to thieno[3,2-b]thiophene precursors through deprotonation at α-positions. Introduction of the sulfur bridge was achieved by Pd-catalyzed coupling reaction with bis(tri-n-butyltin)sulfide (Bu3SnSSnBu3), followed by final ring closure through oxidative coupling with CuCl2. This method achieves higher purity and higher yield than sulfide-quenched LiâBr exchange. UV-vis and fluorescence emission spectra show a bathochromic shift of â10 nm, indicating the introduction of alkyl chains decreases the HOMOâLUMO gap. X-ray analysis yields unit cells for 2,6-bis-octyl and 2,6-bis-dodecyl substituted T5s (C8-T5 and C12-T5, respectively). C8-T5 grows orthorhombic crystals with lattice parameters a = 1.15 nm, b = 0.43 nm and c = 3.05 nm; C12-T5 grows monoclinic crystals (c-unique) with unit cell with parameters a = 1.10 nm, b = 0.42 nm, c = 3.89 nm and γ = 92.9°. Both materials grow large (>50 μm), faceted, single crystals that are microscopically composed of alternating layers of semiconducting cores and insulating substitutions.
最近,噻吩并烯的开发取得了进展,生产出了许多高性能、空气稳定的有机半导体材料。尽管计算研究前景广阔,但五噻吩并烯(T5)薄膜器件的性能却很差,这可能是由于高迁移率各向异性和薄膜形态不佳造成的。我们合成了 2,6-双烷基-五噻吩并烯,通过溶液加工的方法来改善基于 T5 器件的微观结构。噻吩并[3,2-b]噻吩前体通过δ-位的去质子化引入了可溶性侧基。通过钯催化双(三丁基硫化锡)(Bu3SnSSnBu3)偶联反应引入硫桥,然后通过 CuCl2 氧化偶联最终闭环。与硫化物淬灭 LiâBr 交换法相比,这种方法能获得更高的纯度和产率。紫外-可见光谱和荧光发射光谱显示出â10 nm的浴色偏移,表明烷基链的引入减小了HOMOâLUMO间隙。X 射线分析得出了 2,6-双辛基和 2,6-双十二烷基取代 T5s(分别为 C8-T5 和 C12-T5)的单胞。C8-T5 生长正方晶胞,晶格参数为 a = 1.15 nm、b = 0.43 nm 和 c = 3.05 nm;C12-T5 生长单斜晶胞(c-唯一性),单位晶胞参数为 a = 1.10 nm、b = 0.42 nm、c = 3.89 nm 和 δ³ = 92.9°。这两种材料都能生长出大尺寸(大于 50 ¼m)、带刻面的单晶体,这些单晶体在显微镜下由交替的半导体核心层和绝缘取代层组成。