Nascimento Luiza A, Fraysse Kilian S, Krause Kevin, Bentley Cameron L, Han Mingyu, Guijt Rosanne M, Stoddart Paul R, Moulton Simon, Silva Saimon Moraes, Greene George W
The Biomedical and Environmental Sensor Technology (BEST) Research Centre, La Trobe Institute for Molecular Science (LIMS), La Trobe University, Melbourne 3086, Victoria, Australia.
Department of Biochemistry and Chemistry, School of Agriculture, Biomedicine and Environment (SABE), La Trobe University, Melbourne 3086, Victoria, Australia.
ACS Appl Mater Interfaces. 2025 Aug 6;17(31):45042-45055. doi: 10.1021/acsami.5c06970. Epub 2025 Jul 25.
The development of 2D materials is rapidly advancing beyond traditional graphene and metal oxides and into new functional organic materials including conducting polymers (CPs). Synthesizing 2D-CPs, typically achieved by polymerizing within a highly confined space (e.g., between lipid bilayers), is a slow and poorly scalable process that is incapable of producing large area films. A 'tethered-dopant templating' method is used where a surface-grafted layer of dopant molecules regulates the 3D-growth of poly 3,4-ethylenedioxythiophene (PEDOT) allowing ultrathin and molecular-scale '2D' films having thicknesses of just ∼3 nm to be grown in an unconfined geometry over a large area (i.e., cm). While the tethered-dopant template method is a simple and promising alternative to confined geometry templating, the electrochemical mechanisms of film growth and its impact on the film electrochemical properties have yet to be well understood. This investigation shows that the surface-tethered dopant regulates the polymerization reaction by actively suppressing chain termination to support the growth of longer and more conductive chains (i.e., higher charge carrier mobility). These 2D PEDOT films also become 'hyper-doped' with dopant to polymer mass fractions as high as 8:1, resulting in metal-like conductivity due to enhanced charge carrier density. Additionally, 2D PEDOT films achieve unprecedented homogeneity with little variability down to submicrometer length scales. This new understanding into the dopant regulation over electropolymerization combined with the unequaled metal-like conductivity, molecular-scale dimensions, and large area of 2D PEDOT represents a significant advance in CP materials that will drive innovation across numerous fields including transparent conductors, optoelectronics, bionics, and biosensing.
二维材料的发展正在迅速超越传统的石墨烯和金属氧化物，进入包括导电聚合物（CPs）在内的新型功能有机材料领域。合成二维导电聚合物，通常是在高度受限的空间内（如脂质双层之间）进行聚合反应来实现的，这是一个缓慢且难以扩展的过程，无法制备大面积的薄膜。一种“ tethered-dopant templating”方法被采用，其中掺杂剂分子的表面接枝层调节聚3,4-乙撑二氧噻吩（PEDOT）的三维生长，使得厚度仅约3纳米的超薄且分子尺度的“二维”薄膜能够在无约束的几何结构中大面积（即厘米级）生长。虽然tethered-dopant模板法是一种简单且有前景的替代受限几何结构模板法的方法，但薄膜生长的电化学机制及其对薄膜电化学性能的影响尚未得到很好的理解。这项研究表明，表面接枝的掺杂剂通过积极抑制链终止来调节聚合反应，以支持更长且更具导电性的链的生长（即更高的电荷载流子迁移率）。这些二维PEDOT薄膜还会被掺杂剂“超掺杂”，掺杂剂与聚合物的质量分数高达8:1，由于电荷载流子密度增加而导致类似金属的导电性。此外，二维PEDOT薄膜在亚微米长度尺度下实现了前所未有的均匀性，几乎没有变化。对掺杂剂对电聚合反应的调控的这种新理解，再加上二维PEDOT无与伦比的类似金属的导电性、分子尺度尺寸和大面积，代表了导电聚合物材料的重大进展，将推动包括透明导体、光电子学、仿生学和生物传感在内的众多领域的创新。
