Pagaduan James Nicolas, Hight-Huf Nicholas, Zhou Le, Dix Nicholas, Premadasa Uvinduni I, Doughty Benjamin, Russell Thomas P, Ramasubramaniam Ashwin, Barnes Michael, Katsumata Reika, Emrick Todd
Polymer Science and Engineering Department, University of Massachusetts, Amherst, Massachusetts 01003, United States.
Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States.
ACS Cent Sci. 2024 Aug 6;10(8):1629-1639. doi: 10.1021/acscentsci.4c00704. eCollection 2024 Aug 28.
Understanding the electronic properties resulting from soft-hard material interfacial contact has elevated the utility of functional polymers in advanced materials and nanoscale structures, such as in work function engineering of two-dimensional (2D) materials to produce new types of high-performance devices. In this paper, we describe the electronic impact of functional polymers, containing both zwitterionic and fluorocarbon components in their side chains, on the work function of monolayer graphene through the preparation of negative-tone photoresists, which we term "fluorozwitterists." The zwitterionic and fluorinated groups each represent dipole-containing moieties capable of producing distinct surface energies as thin films. Kelvin probe force microscopy revealed these polymers to have a -doping effect on graphene, which contrasts the work function decrease typically associated with polymer-to-graphene contact. Copolymerization of fluorinated zwitterionic monomers with methyl methacrylate and a benzophenone-substituted methacrylate produced copolymers that were amenable to photolithographic fabrication of fluorozwitterist structures. Consequently, spatial alteration of zwitterion coverage across graphene yielded stripes that resemble a lateral -- diode configuration, with local increase or decrease of work function. Overall, this polymeric fluorozwitterist design is suitable for enabling simple, solution-based surface patterning and is anticipated to be useful for spatial work function modulation of 2D materials integrated into electronic devices.
了解软硬材料界面接触所产生的电子特性，提高了功能聚合物在先进材料和纳米结构中的应用价值，例如在二维（2D）材料的功函数工程中用于制造新型高性能器件。在本文中，我们通过制备负性光刻胶（我们称之为“氟两性离子光刻胶”），描述了侧链同时含有两性离子和碳氟化合物成分的功能聚合物对单层石墨烯功函数的电子影响。两性离子基团和氟化基团各自代表能够作为薄膜产生不同表面能的含偶极部分。开尔文探针力显微镜显示这些聚合物对石墨烯具有n型掺杂效应，这与通常与聚合物 - 石墨烯接触相关的功函数降低形成对比。将氟化两性离子单体与甲基丙烯酸甲酯和二苯甲酮取代的甲基丙烯酸酯进行共聚，得到了适用于光刻制造氟两性离子光刻胶结构的共聚物。因此，石墨烯上两性离子覆盖的空间变化产生了类似于横向n - p二极管配置的条纹，功函数局部增加或减少。总体而言，这种聚合物氟两性离子光刻胶设计适用于实现基于溶液的简单表面图案化，并有望用于集成到电子器件中的二维材料的空间功函数调制。
