Extended π-Conjugated Molecules Derived from Naphthalene Diimides toward Organic Emissive and Semiconducting Materials
摘要:
In this paper, a new synthetic way to modify naphthalene diimide (NDI) at "shoulder" positions is reported. The key step of the transformation is the intramolecular cyclization involving ethynyl and imidecarbonyl groups. The structure of the intermediate pyrylium cation was confirmed by X-ray crystal structural analysis. New conjugated molecules 1a-g were successfully synthesized in acceptable yields. Their absorption and fluorescence spectra were measured. Among them 1c-f are strongly emissive in solutions. Furthermore, 1b-f are also fluorescent in their solid states; in particular, 1b exhibits a typical aggregation-induced enhanced emission feature. Yellow-emissive microfibrils of Id show potential optical waveguide behavior. HOMO/LUMO energies of 1a-f were determined based on their cyclic voltammograms. The results also reveal that HOMO/LUMO energies of these new conjugated molecules are influenced by the two flanking moieties. Notably, the thin film of 1c that is emissive shows p-type semiconducting behavior with hole mobility up to 0.0063 cm(2) V-1 s(-1) based on the transfer and output characteristics of the OFET (organic field effect transistor).
据报道,具有发光和半导体功能的新型芳基乙炔取代的萘二酰亚胺(NDI)1-6。其中,确定了1的晶体结构。根据它们的还原电势和薄膜吸收光谱,估算了这些改性NDI的HOMO / LUMO能量。结果表明,侧基的芳基对它们的HOMO / LUMO能量有轻微的影响。这些NDI的发射颜色从绿色到红色不等,有趣的是,它们显示出聚集诱导的发射增强行为,固态时的荧光量子产率达到9.86%。的微米棒1,3,及5显示出具有相对较低的光损耗系数的典型光波导行为。具有这些NDI薄膜的有机场效应晶体管是采用常规技术制造的。结果表明的那薄膜2,4,和6,长链和支链烷基链,显示空气稳定的n型半导体与最多的电子迁移率的性质0.035厘米2 V -1 小号-1热处理后,而1,3和5,具有短烷基链,表现为与最多的电子迁移率在氮气氛下的n型半导体,以0.075厘米2 V -1热退火后的 s -1。