Cendra Camila, Balhorn Luke, Zhang Weimin, O'Hara Kathryn, Bruening Karsten, Tassone Christopher J, Steinrück Hans-Georg, Liang Mengning, Toney Michael F, McCulloch Iain, Chabinyc Michael L, Salleo Alberto, Takacs Christopher J
Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States.
Physical Science and Engineering Division KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
ACS Macro Lett. 2021 Oct 19;10(10):1306-1314. doi: 10.1021/acsmacrolett.1c00547. Epub 2021 Oct 5.
A new class of donor-acceptor (D-A) copolymers found to produce high charge carrier mobilities competitive with amorphous silicon (>1 cm V s) exhibit the puzzling microstructure of substantial local order, however lacking long-range order and crystallinity previously deemed necessary for achieving high mobility. Here, we demonstrate the application of low-dose transmission electron microscopy to image and quantify the nanoscale and mesoscale organization of an archetypal D-A copolymer across areas comparable to electronic devices (≈9 μm). The local structure is spatially resolved by mapping the backbone (001) spacing reflection, revealing nanocrystallites of aligned polymer chains throughout nearly the entire film. Analysis of the nanoscale structure of its ordered domains suggests significant short- and medium-range order and preferential grain boundary orientations. Moreover, we provide insights into the rich, interconnected mesoscale organization of this new family of D-A copolymers by analysis of the local orientational spatial autocorrelations.
一类新型的供体-受体（D-A）共聚物被发现能产生与非晶硅相媲美的高电荷载流子迁移率（>1 cm² V⁻¹ s⁻¹），然而，其微观结构令人费解，具有大量的局部有序性，但缺乏先前认为实现高迁移率所必需的长程有序性和结晶性。在这里，我们展示了低剂量透射电子显微镜在成像和量化典型D-A共聚物在与电子器件相当的区域（≈9 μm）内的纳米级和介观尺度组织方面的应用。通过绘制主链（001）间距反射图来解析局部结构，揭示了几乎整个薄膜中排列的聚合物链的纳米微晶。对其有序域的纳米级结构分析表明存在显著的短程和中程有序以及优先的晶界取向。此外，通过分析局部取向空间自相关，我们深入了解了这个新的D-A共聚物家族丰富的、相互关联的介观尺度组织。
