Thermal And Mechanics Analysis On Stretchable Electronics

Flexible electronics industry relies on an electronic device intergration on a flexible or stretchable thin elastomer substrate. These products have characteristics of bendable, malleable, and controllable fatigue life. In contrast, conventional photolithographic techniques address difficulty in achieving large-format, non-planar, low-temperature manufacturing and other issues, and the organic material compatibility is unsatisfactory; high manufacturing costs can not make the flexible electronic devices open to industry.An injectable micro-optoelectronic device is a typical application in this area. The thermal behavior of μ-LEDs array structure is very important in the explanted piece of tissue in mouse brain because the excessive heat may result in tissue damage or adverse reactions. To better understand the operation and establish general guidelines for designing μ-LEDs, minimizing the thermal effect of the device, the thesis presents a theoretical model for pulse mode operation, verified by finite element analysis(FEA) and experimental verification. This article has not only proposed a theoretical maximum temperature increase of μ-LEDs array structure, but also established a simple scaling law that would affect the maximum temperature. It can be used to optimize the performance of the device.High areal coverage GaAs photovoltaics intergrated with a thin layer of substrate is another application in this field. Through finite element analysis(FEA) and theoretical analysis, the thesis presents a reasonable mechanical design and FEA model. The proposed structure of the substrate, called island-bridge configuration, with serpentine interconnect pattern meets up to 91% of the areal coverage of functional photovoltaics and also local stretchability of as large as 440% is achieved, ensuring high energy harvesting and storage. The width of the trench is only 0.25 mm, depth 0.2mm. The extremely thin substrate can be better integrated into the roof, and even wearable devices, to meet the different needs from civilian and military. Without compromising the system stretchability of 20%, the interconnect structure is specifically designed by using a periodic serpentine array structure and Ecoflexas the material for the base layer. It can sustain up to 440% of stretching deformation under yiled strain criterion 0.3% of metallic copper, which means that the photovoltaic device can guarantee fatigue behaviors.