Origami and Kirigami Design Principles for Optical Tracking, Energy Harvesting, and Other Applications

Abstract

Origami and kirigami (the folding and cutting of paper, respectively, to achieve a desired shape) have been used in engineering to develop airbags, optical components, deployable spaceborne solar arrays, reprogrammable metamaterials, and load-bearing metal structures. Despite these efforts however, little has been shown beyond the packaging and load-bearing advantages of these three-dimensional approaches to structural design. This dissertation describes the use of dynamic, three-dimensional design principles to develop multifunctional mechanical and optoelectronic devices with improved performance, decreased fabrication costs, and greater economic value. First, we introduce a novel method of integrated, low-profile solar tracking whereby a simple kirigami pattern in thin-film gallium-arsenide solar cells enables tracking at the substrate level simply by stretching the sheet. The new tracker is inherently lightweight and very low profile; it is less susceptible to wind loading, which greatly reduces tracking system complexity, size, and cost, while also enabling new applications. System performance is considered as a function of cut geometry, materials selection, and geographic location, and optimized trackers are shown to generate up to 40% more energy per solar cell area over the course of a day relative to a stationary, flat panel module. Electrical and mechanical robustness are also considered with implications towards long-term solar tracking applications (i.e. >10,000 actuation cycles). Subsequently, we discuss a multifunctional system that combines kirigami solar tracking and integrated concentration optics to further reduce the overall cost of solar electricity. Optical design, mechanical response, and materials selection are considered to maximize optical and power concentration factor while also maintaining a simple design philosophy. The final system is shown to provide ~60x solar concentration, and further modifications will enable power concentration factors greater than 100x. Finally, similar design principles are extended to develop new applications including textured surfaces for flow manipulation and drag steering, kirigami patterns for tunable antennas, and origami tessellations for novel forms of electrochemical energy storage.