Wearable electronics are produced by depositing thin electroconductive layers with low resistance on flexible substrates. In the process of producing such metallic films, as well as during their usage, structural defects may appear which affect their electrical properties. In this paper, we present analytical and numerical models for understanding phenomena related to the electrical conductivity of thin electroconductive layers. The algorithm in the numerical model is based on the boundary integral equation method. The formulas enable calculation of the potential distribution and electric field strength of the analyzed structures, and describe the impact of cracks on their electrical resistance. The validity of the proposed models was verified by experimental results.

No abstract

Continuity of the conductive path is a prerequisite for the phenomenon of electric current to exist in the structures of wearable electronics. The value of the current depends not only on the material properties of the structure but also on the geometrical dimensions of the defect of a thin electrically conductive layer. The article describes the analysis of the influence of the width and slope of the linear defect of a thin metallic layer on the value of the current. The conducted simulations show that when the width of the defect is smaller than 40% of the distance of the defect from the edge of the path, the current intensity depends on the ratio of the width to the length of the defect to a very small extent. The value of the current also depends on the slope of the defect to the path axis. In the case of a larger number of defects, their influence on the effective track resistance depends not only on their size but also on their location and distance from each other. The resistance of the entire electrically conductive layer is also influenced by the location of defects in relation to its edges.

No abstract

The paper presents an analysis of the influence of microcracks in textronic conductive layers on their conductive properties. The tested structures were created in the physical vacuum deposition process. The paper presents the results of computer simulations of the current flow field in thin conductive stripes with defects distributed along a line perpendicular to the stripe axis and randomly placed on its entire surface. It was found, inter alia, that a larger number of shorter collinear defects may have many times lower resistance than a small number of longer defects of the same total length (e.g., with 40 collinear cracks with a total length of 90% of the strip width, the sheet resistance is only about 3% greater compared to a track without cracks). It was found that the percolation threshold of the tested models with square proportions and randomly selected defects is close to the value of 0.5. This is consistent with the theoretical calculations for analogous discrete models with infinite sizes. It was also found that the sheet resistance of the conductive strip with randomly distributed defects clearly depends on its length when the defect concentration exceeds 20%. The simulations were carried out on the basis of the integral equation method, with the solution presented in the form of double layer potentials.