We report on the synthesis and characterization of a novel naphthalene diimide (NDI)-based small molecule with a bithiophene linker unit, NDI-BT-NDI-EH, for application as a solution-processable n-channel active material in organic field-effect transistors (OFETs). NDI-BT-NDI-EH was synthesized via the Stille coupling reaction and the bithiophene linker unit was introduced as a rotatable linker between two NDI cores to improve the solubility of NDI-BT-NDI-EH while maintaining its high field-effect mobility. We found that the crystallinity and molecular ordering of NDI-BT-NDI-EH thin films could be improved by thermal annealing; a moderate annealing temperature of 120 °C appeared to be optimal for promoting self-organization among the NDI-BT-NDI-EH molecules. The NDI-BT-NDI-EH molecules in thermally annealed thin films mainly adopted an edge-on orientation with improved π-π stacking on the surface of octyltrichlorosilane-treated SiO₂ substrates, which is favorable for lateral charge transport. As a result, the optimally annealed NDI-BT-NDI-EH OFET exhibited evident n-type OFET characteristics with high field-effect mobilities of up to 0.016 cm² V⁻¹ s⁻¹ and an on/off ratio of 1.4 × 10⁵.

我们报告了基于新型萘二酰亚胺（NDI）的具有联噻吩接头单元NDI-BT-NDI-EH的小分子的合成和表征，用于在有机场效应中作为溶液可加工的n通道活性材料晶体管（OFET）。NDI-BT-NDI-EH通过引入Stille偶联反应和联噻吩接头单元作为两个NDI核之间的可旋转接头，以提高NDI-BT-NDI-EH的溶解度，同时保持其高场效应迁移率。我们发现通过热退火可以改善NDI-BT-NDI-EH薄膜的结晶度和分子有序性。120℃的适度退火温度似乎是促进NDI-BT-NDI-EH分子之间自组织的最佳选择。热退火薄膜中的NDI-BT-NDI-EH分子主要采用边沿取向，在辛基三氯硅烷处理的SiO ₂表面上具有改善的π - π堆积衬底，有利于横向电荷传输。结果，最佳退火的NDI-BT-NDI-EH OFET表现出明显的n型OFET特性，具有高达0.016 cm ²  V ^-1  s ^-1的高场效应迁移率和1.4×10的开/关比⁵。