自组装单分子膜功能器件  

Functional Self-assembled Monolayer Devices

作　　者：张召阳 李涛[1] Zhao-yang Zhang;Tao Li(School of Chemistry and Chemical Engineering,Shanghai Jiao Tong University,Shanghai 200240)

机构地区：[1]上海交通大学化学化工学院,上海200240

出　　处：《高分子学报》2021年第6期602-616,I0003,共16页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号22022507,51973111)资助项目.

摘　　要：分子尺度电子学是利用单个分子或分子单层组装体作为活性单元来实现电子学功能的一门前沿科学领域.基于自组装单分子膜(SAMs)的分子器件在分子电子学的实用化道路上具有很大的发展潜力与应用前景.目前,SAMs功能器件的研究仍处于起步阶段,其性能还有很大提升空间.本文首先评述了SAMs器件的构筑方法,针对直接蒸镀金属顶电极会对SAMs造成破坏的问题,介绍了3类软接触电极,包括液态金属、导电高分子和石墨烯顶电极;然后以固态光开关器件为例介绍了近年来功能器件上的一些新进展,分子优化设计对于提升器件响应活性具有重要意义;同时总结了共轭聚合物SAMs器件的制备方法和性能,通过合理的结构设计,共轭聚合物能进行电荷的长程输运,并有望提供比小分子更优异的光电功能;最后讨论和展望了未来的发展方向.Molecular-scale electronics is a cutting edge research field aimed at achieving electronic functions by utilizing single molecules and their monolayer assemblies as active components.Molecular devices based on self-assembled monolayers(SAMs)show high potential towards the application of molecular electronics in the future.However,the development of functional SAM devices is still in its infancy,and their performance is far from meeting the requirements of practical applications.In this review,we first summarize the methods for fabricating SAM devices using soft top-contact electrodes,including liquid metals(mercury and Ga/In eutectic),conductive polymers(e.g.,PEDOT:PSS)and graphene,and graphene has been considered as an ideal choice for building SAM devices because of it high electrical conductivity,mechanical flexibility,chemical stability,optical transparency and processability.Then we introduce recent progress on functional SAM devices,especially solid-state photoswitchable devices,and we highlight that rational molecular design(anchor,linker,and functional group)is crucial for improving the device performance.For example,molecular engineering strategies overcoming intermolecular steric hindrance can boost the photoisomerization ability of azobenzenes in SAMs and thus the photo-responsibility of their photoswitchable devices.We also provide an overview on how to fabricate conjugated polymers based SAM devices and discuss their charge transport behaviors in two kinds of junctions,i.e.,vertical and planar junctions.These results indicate that conjugated polymerss are distinct from small molecular materials and may hold advantages in optoelectronic functions.For example,properly designed conjugated polymers can mediate long-range charge transport and thus act as molecular wires.Moreover,functional SAM devices based on conjugated polymers can outperform the small molecular counterpart on key device performance,such as on-off ratios for optoelectronic switches.Finally,a perspective on future research directions and

关 键 词：分子电子学 自组装单分子膜 分子器件 共轭聚合物 

分 类 号：TN03[电子电信—物理电子学] TQ317[化学工程—高聚物工业] O641.3[理学—物理化学]