Electrical performance evolution and fatigue mechanisms of silver-filled polymer ink under uniaxial cyclic stretch
Electrical performance evolution and fatigue mechanisms of silver-filled polymer ink under uniaxial cyclic stretch
复制标题
DOI：
10.1088/2058-8585/ac1243
复制
发表时间：
2021
影响因子：
3.1
通讯作者：
G. Cahn;O. Pierron;A. Antoniou
中科院分区：
文献类型：
--
作者：
G. Cahn;O. Pierron;A. Antoniou
柔性混合电子器件依赖于顺应性互连，以便在需要重复伸长（包括重复拉伸）的情况下保持性能完整性。一类这样的导电互连是聚合物与导电颗粒的复合材料，其可以在高应变下拉伸而不会发生电路故障。然而，到目前为止，它们的疲劳响应在很大程度上仍未被探索，并且在用于健康监测应用之前是必不可少的。在这项研究中，一个可拉伸的银填充导体进行评估下的高应变循环。原位技术，包括四点电阻测量和激光轮廓术，被用来关联的电气性能的疲劳响应的变化。在第一次加载循环期间，表面裂纹形成在拉伸时是广泛的，在较高应变下形成高度互连的裂纹网络，其不会立即导致开路失效。电阻随着循环的增加归因于这些裂纹的逐渐加深，直到它们的深度接近膜厚度，最终导致电气故障。疲劳寿命，达到预定的电气性能极限所需的周期数，被证明是最受影响的施加的应变幅度。采用R/R 0 = 500的标准化电阻增长极限，发现500 μm宽的导线在35%的应变幅下可以承受23次循环，而当应变幅下降到5%时，可以承受500多次循环。对平均应变的灵敏度，Δ m，与低于15%的应变幅度有关。以这种方式，复合导体显示出与均匀金属膜明显不同的裂纹演化行为。
Flexible hybrid electronics rely upon compliant interconnects in order to maintain performance integrity in cases that require repeated elongation, including repeated stretching. A class of such conductive interconnects are composites of polymer with conductive particles that can be stretched at high strains without circuit failure. However, their fatigue response has so far remained largely unexplored and is essential prior to using in health monitoring applications. In this research, a stretchable silver-filled conductor is evaluated under high-strain cycling. In-situ techniques, including four-point resistance measurement and laser profilometry, are used to correlate changes in electrical performance to the fatigue response. Surface crack formation is extensive upon stretching during the first loading cycle, forming a heavily interconnected crack network at higher strains that does not immediately result in open circuit failure. Resistance increase with cycling is attributed to a gradual deepening of these cracks until their depths approach the film thickness, eventually leading to electrical failure. Fatigue life, the number of cycles required to reach a predetermined electrical performance limit, is shown to be most influenced by the applied strain amplitude. Using a normalized resistance increase limit of R/R 0 = 500, it is found that 500 μm wide conductive lines endure 23 cycles at 35% strain amplitude, but this becomes over 500 cycles when the amplitude is dropped to 5%. Sensitivity to mean strain, ϵ m, is relevant to strain amplitudes below 15%. In this manner, a composite conductor was shown to exhibit crack evolution behavior distinctly different from homogeneous metallic films.