【摘要】 近年来,有机半导体的开发及应用推动了有机光电器件的迅速发展。其中小分子半导体器件相比聚合物半导体器件具有更好的重现性和可控性,制备工艺更多样化,界面调控更简单且机理更清晰。然而,小分子半导体在成膜设备和成膜工艺方面要求相对更高,尤其是工艺参数对膜中分子聚集态和取向性有显著影响。目前,小分子半导体材料存在的不足在于:(1)常规制备工艺难以获得分子排列高度有序的薄膜;(2)可同时蒸镀和溶液加工的小分子半导体相对缺乏;(3)光吸收范围相对较窄且激子扩散长度较短。2009年首次报道的二萘嵌苯类小分子半导体四苯基二苯并荧蒽(Tetraphenyldibenzoperiflanthene,DBP)及其衍生物二茚并苝(Diindenoperylene,DIP)凭借优异的光电性能,如DBP在可见光区强吸收、双极传输特性、高空穴迁移率、强水平分子取向趋势、高光/热稳定性以及DIP的双极传输特性、垂直分子取向和高结晶性等,引起了越来越多的关注。近年来,研究者们主要从设备改造、制备工艺、器件结构和材料匹配等方面进行尝试,不断提升基于DBP和DIP的有机光电器件的性能。DBP和DIP在有机光伏电池、有机发光二极管、有机晶体管中被有效应用。主要通过热退火和溶剂蒸气退火工艺提升DBP光伏电池的光电流、填充因子,并将DBP作为受体匹配合适的给体或将DBP与非富勒烯受体匹配后获得更高的开路电压。在基于DBP的有机发光二极管和有机场效应晶体管方面,主要研究了器件性能与缓冲层传输特性、发光层结构、基板温度和沟道长度等之间的关联性。关于DIP薄膜,近几年的研究工作将角度倾斜沉积、温度控制、退火工艺、分子模板等手段引入到薄膜分子取向调控中。并利用DIP的双极传输制备了基于DIP给体或DIP受体的光伏电池,获得了较高的电池效率(5. 8%)。此外,通过易结晶的DIP诱导其他半导体材料的分子排列提升有机场效应晶体管的迁移率。本文系统综述了DBP和DIP的材料特性及其在上述多种有机光电器件中的重要研究进展,并对其研究趋势进行了深度展望,以期为这类小分子半导体的分子设计及应用提供参考。更多还原

【Abstract】 In recent years,the application of organic semiconductors has promoted the rapid development of organic optoelectronics. Compared with polymer semiconductor devices,small-molecule semiconductor devices have better reproducibility and controllability,more diversified fabrication processes,simpler interface regulation and clearer mechanism. However,small-molecule semiconductors have higher requirement in equipment and process,especially the process parameters exert a significant influence on the molecular aggregation state and orientation in the film. Currently the disadvantages of small-molecule semiconductor materials are as follows:( 1) it is difficult to obtain thin films with highly ordered molecular arrangement via conventional fabrication process;( 2) small-molecule semiconductors which can be fabricated by evaporation and solutionprocessing are relatively lack;( 3) the optical absorption range is relatively narrow and the exciton diffusion length is shorter.Small molecules of tetraphenyldibenzoperiflanthene( DBP) reported firstly in 2009 and its derivative diindenoperylene( DIP) show excellent photoelectronic properties. DBP demonstrates strong visible absorption,bipolar transport,high hole-mobility,strong trend of horizontal molecular orientation,high light-and thermal-stability. DIP indicates bipolar transport,perpendicular molecular orientation,and apparent crystallinity. Therefore,DBP and DIP have attracted more and more scientists’ attention. In recent years,researchers have mainly tried to improve the performance of organic optoelectronic devices based on DBP and DIP by equipment modification,fabrication process,device structure,and material matching and so on.DBP and DIP have been efficiently applied in organic solar cells( OSC),organic light emitting diodes( OLED),and organic field effect transistors( OFET). The photocurrent and filling factor of DBP photovoltaic cells were increased by thermal annealing and solvent vapor annealing,and higher open-circuit voltage was obtained by using DBP as acceptor or matching DBP donor with non-fullerene acceptor. For DBP-based OLED and OFET,the correlation between device performance and the transport characteristics of buffer layers,the emitting layer structure,the substrate temperature,and the channel length are mainly studied. With regard to the DIP thin films,in recent years the methods of oblique grazing angle deposition,temperature control,annealing process,and molecular template have been introduced into the regulation of molecular orientation in thin films. The OSCs based on DIP donor or DIP receptor were prepared due to the bipolar transport of DIP and achieved high efficiency of 5. 8%. In addition,the molecular arrangement of other semiconductors is guided by the crystalline DIP to increase the mobility of the OFETs.This paper systematically reviews the DBP and DIP properties and the important research progress in many kinds of organic optoelectronic devices. Finally,the development tendency in the future of organic optoelectronic devices based on DBP and DIP is prospected,hoping to provide a reference for the molecular design and application of such type of small molecular semiconductors.更多还原