Chae Youngchul, Bae Juyeol, Lim Kyoungyoung, Kim Taesung
Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST) 50 UNIST-gil Ulsan 44919 Republic of Korea
RSC Adv. 2022 Sep 29;12(43):27846-27854. doi: 10.1039/d2ra05551a. eCollection 2022 Sep 28.
Next-generation electronic devices require electrically conductive, mechanically flexible, and optically transparent conducting electrodes (CEs) that can endure large deformations. However, patterning conditions of such CEs have been mainly limited to flat substrates because of the nature of conventional fabrication techniques; thus, comprehensive studies are needed to be conducted on this topic. Herein, we characterize the material and structural properties of CEs, curvature of substrates, and their operational performance. We use a single-step printing method, termed template-guided foaming (TGF), to fabricate flexible transparent conducting electrodes (FTCEs) on various substrates with initial curvatures. We adopted silver nanowires (AgNWs) and a conductive polymer (PEDOT:PSS) to characterize and compare the effect of initial substrate curvatures on the sheet resistance during inward and outward bending. The AgNW-based grids exhibited a considerably low sheet resistance, which was linearly proportional to the working curvature of the substrate, whereas PEDOT:PSS-based grids exhibited a relatively higher sheet resistance, which increased regardless of the initial and working curvatures of the substrate. Although both CE grids exhibited a high flexibility and transmittance during 10 000 cyclic tests, the initial curvature of the substrate affected the sheet resistance; hence, operational conditions of FTCEs must be considered to improve the repeatability and durability of such FTCE-integrated devices. Finally, we believe that our study introduces a novel methodology for the design, fabrication, and operation strategy of flexible electronic devices and wearable devices with high performances.
下一代电子设备需要具备导电、机械柔性和光学透明的导电电极（CE），且这些电极要能承受大变形。然而，由于传统制造技术的特性，此类CE的图案化条件主要局限于平坦基板；因此，需要对这一主题进行全面研究。在此，我们对CE的材料和结构特性、基板的曲率及其操作性能进行了表征。我们使用一种称为模板引导发泡（TGF）的单步印刷方法，在具有初始曲率的各种基板上制造柔性透明导电电极（FTCE）。我们采用银纳米线（AgNWs）和导电聚合物（PEDOT:PSS）来表征和比较初始基板曲率对内弯和外弯过程中薄层电阻的影响。基于AgNW的网格表现出相当低的薄层电阻，它与基板的工作曲率成线性比例，而基于PEDOT:PSS的网格表现出相对较高的薄层电阻，无论基板的初始曲率和工作曲率如何，其都会增加。尽管两种CE网格在10000次循环测试中都表现出高柔韧性和透光率，但基板的初始曲率会影响薄层电阻；因此，必须考虑FTCE的操作条件，以提高此类集成FTCE设备的重复性和耐用性。最后，我们相信我们的研究为高性能柔性电子设备和可穿戴设备的设计、制造和操作策略引入了一种新方法。
