Sturdza Bernd K, Jacobus Nicole, Bennett Andre, Form Joshua, Wood Louis, Christoforo M Greyson, Riede Moritz K, Nicholas Robin J
Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, U.K.
ACS Appl Electron Mater. 2025 May 29;7(11):4738-4746. doi: 10.1021/acsaelm.4c02246. eCollection 2025 Jun 10.
Transparent conductive films are key components of many optoelectronic devices but are often made from either scarce or brittle materials like indium tin oxide. Carbon nanotube-polymer films offer an abundant and flexible alternative. Here, we report how the dimensions of the carbon nanotube raw material affect their thin film performance and thickness yield when processed with the polymer ethylene-vinyl acetate. We perform chemical doping with several halogenated metals and find the electron affinity of the metal to be a good indicator of p-doping effectiveness. We identify CuCl as low-cost alternative to the established gold chloride dopants. Optimising the dopant deposition method allows us to reduce the effect of doping on the optical transmittance. Percolation analysis of our films demonstrates that optimized single-walled carbon nanotube-ethylene-vinyl acetate films show no sign of percolation effects down to thicknesses of 5 nm. Finally, we produce transparent touch-sensitive devices. Comparing several of these devices, we find a linear relationship between the sheet resistance and the on/off ratio of the touch sensing that can be used to determine a threshold film thickness. Using doped carbon nanotube-ethylene-vinyl acetate films increases the on/off ratio and allows us to fabricate touch-sensitive devices with an on/off ratio of 10 at 95% optical transmittance. This clearly demonstrates the potential of these films for transparent touch-sensitive applications.
透明导电薄膜是许多光电器件的关键组件，但通常由铟锡氧化物等稀缺或易碎材料制成。碳纳米管 - 聚合物薄膜提供了一种丰富且灵活的替代方案。在此，我们报告了碳纳米管原材料的尺寸如何影响其与聚合物乙烯 - 醋酸乙烯酯加工时的薄膜性能和厚度成品率。我们用几种卤化金属进行化学掺杂，发现金属的电子亲和力是p型掺杂有效性的良好指标。我们确定氯化铜是已确立的氯化金掺杂剂的低成本替代品。优化掺杂剂沉积方法使我们能够降低掺杂对光学透过率的影响。对我们的薄膜进行的渗流分析表明，优化后的单壁碳纳米管 - 乙烯 - 醋酸乙烯酯薄膜在低至5纳米的厚度下没有渗流效应的迹象。最后，我们制作了透明触敏器件。比较其中几种器件，我们发现薄层电阻与触摸感应的开/关比之间存在线性关系，可用于确定阈值薄膜厚度。使用掺杂的碳纳米管 - 乙烯 - 醋酸乙烯酯薄膜可提高开/关比，并使我们能够制造出在95%光学透过率下开/关比为10的触敏器件。这清楚地证明了这些薄膜在透明触敏应用中的潜力。
