The tuning of the energy levels of dibenzosilole copolymers and applications in organic electronics
作者:Colin W. Keyworth、Khai Leok Chan、John G. Labram、Thomas D. Anthopoulos、Scott E. Watkins、Mary McKiernan、Andrew J. P. White、Andrew B. Holmes、Charlotte K. Williams
DOI:10.1039/c1jm11242b
日期:——
An understanding of the structure–function relationships of conjugated polymers is an invaluable resource for the successful design of new materials for use in organic electronics. To this end, we report the synthesis, characterisation and optoelectronic properties of a range of new alternating copolymers of dibenzosilole. Suzuki polycondensation reactions were used to afford a series of eight conjugated materials by the respective combination of either a 3,6- or 2,7-linked 9,9-dioctyldibenzosilole with 3,6-linked-N-octylcarbazole, triarylamine, oxadiazole and triazole monomers. The copolymers were fully characterised using 1H, 13C1H} NMR spectroscopy, size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The photophysical properties were determined using UV-Vis spectroscopy, photoluminescence (PL) measurements, cyclic voltammetry (CV) and photoelectron emission spectroscopy in air (PESA). The spectroscopic and electrochemical measurements were used to determine the materials' HOMO and LUMO energies and the values were correlated with the copolymer composition and structure. A selection of the copolymers (P4, P5 and P8) were evaluated as the active layer within single-layer polymer light emitting diodes (PLEDs), with the configuration: glass/ITO/PEDOT:PSS/emissive layer/Ba/Al, which gave low intensity electroluminescence. The selected copolymers were also evaluated as the organic semiconductor in bottom-gate, bottom-contact organic field effect transistors (OFETs). The best performing devices gave a maximum mobility of 3 × 10−4 cm2 V−1s−1 and on/off current ratios of 105.
对共轭聚合物的结构-功能关系的理解是成功设计用于有机电子器件的新材料的重要资源。为此,我们报道了一系列新的交替共聚物的合成、表征和光电特性,这些聚合物基于二苯硅烯。通过铃木聚合反应,我们合成了一系列八种共轭材料,它们是将3,6-或2,7-连接的9,9-二辛基二苯硅烯与3,6-连接的N-辛基卡巴唑、三芳胺、噁二唑和三唑单体相结合而得到的。我们使用1H和13C1H} NMR光谱、尺寸排斥色谱(SEC)、差示扫描量热法(DSC)和热重分析(TGA)对共聚物进行了全面表征。利用紫外-可见光光谱、光致发光(PL)测量、循环伏安法(CV)和空气中的光电子发射光谱(PESA)确定了光物理性质。通过这些光谱和电化学测量,我们确定了材料的HOMO和LUMO能量,并将这些值与共聚物的组成和结构相关联。选择的共聚物(P4、P5和P8)作为单层聚合物发光二极管(PLEDs)的活性层进行评估,配置为:玻璃/ITO/PEDOT:PSS/发光层/Ba/Al,结果显示出低强度的电致发光。这些选定的共聚物也作为底栅、底接触有机场效应晶体管(OFETs)的有机半导体进行评估。表现最好的器件达到了最高的迁移率3 × 10−4 cm2 V−1s−1和开关电流比105。