RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
Center for Polymers and Organic Solids, University of California, Santa Barbara, CA, 93106, USA.
Sci Rep. 2018 Jan 11;8(1):481. doi: 10.1038/s41598-017-18881-y.
Preparation of highly crystalline organic semiconductor films is vital to achieving high performance in electronic devices. Here we report that surface segregated monolayers (SSMs) on top of phenyl-C-butyric acid methyl ester (PCBM) thin films induce crystal growth in the bulk, resulting in a dramatic change in the structure to form a new crystal phase. Highly ordered crystalline films with large domain sizes of several hundreds of nanometers are formed with uniaxial orientation of the crystal structure perpendicular to the substrate. The molecular rearrangements in SSMs trigger the nucleation at a lower temperature than that for the spontaneous nucleation in PCBM. The vertical charge mobility in the SSM-induced crystal domains of PCBM is five times higher than in the ordinary polycrystalline domains. Using surface monolayers may be a new strategy for controlling crystal structures and obtaining high-quality organic thin films by post-deposition crystallization.
高度结晶的有机半导体薄膜的制备对于实现电子器件的高性能至关重要。在这里，我们报告说，在苯基-C-丁酸甲酯（PCBM）薄膜顶部的表面分离单层（SSM）诱导体相中的晶体生长，导致结构发生剧烈变化，形成新的晶体相。具有数百纳米大小的大畴的高度有序的结晶膜具有与衬底垂直的晶体结构的单轴取向。SSM 中的分子重排触发了比 PCBM 中自发成核更低的温度下的成核。在 SSM 诱导的 PCBM 晶体畴中的垂直电荷迁移率比普通多晶畴中的高五倍。使用表面单层可能是通过后沉积结晶来控制晶体结构和获得高质量有机薄膜的新策略。
