Developing electronics in unconventional forms provides opportunities to expand the use of electronics in diverse applications including bio-integrated or implanted electronics. One of the key challenges lies in integrating semiconductor microdevices onto unconventional substrates without glue, high pressure or temperature that may cause damage to microdevices, substrates or interfaces. This paper describes a solution based on natural gecko setal arrays that switch adhesion mechanically on and off, enabling pick and place manipulation of thin microscale semiconductor materials onto diverse surfaces including plants and insects whose surfaces are usually rough and irregular. A demonstration of functional 'geckoprinted' microelectronic devices provides a proof of concept of our results in practical applications.

The recent commercial success of flexible and foldable displays has resulted in growing interest in stretchable electronics which are considered to be the next generation of the optoelectronic technology. Stretchable display technologies are being intensively studied for versatile applications including wearable, attachable, and shape changeable electronics. In this paper, we present high fill factor, stretchable inorganic light-emitting diode (LED) displays fabricated by connecting mini-LEDs and stretchable interconnects in a double-layer modular design. The double-layer modular design enables an increased areal coverage of LEDs and stretchable interconnectors with both electrical and mechanical stability. The main features of the double-layer modular design, fabrication processes, and device characteristics for the high fill factor, stretchable inorganic LED display are discussed, with experimental and computational results. Demonstrations of a passive matrix LED display confirm the potential value of the multi-layer structured, stretchable electronics in a wide range of applications that need high fill factor with high stretchability.

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Concentrated photovoltaics allow a reduction of expensive semiconductor materials by collecting incident light through optical elements such as lenses and/or mirrors, which usually require bulky or heavy dual‐axis solar trackers, requiring dedicated installation sites. In this paper, we report a planar‐type concentrating photovoltaics with cylindrical lenses on which flexible GaAs solar cells are directly integrated on the curvilinear surfaces. The planar‐type concentrating system maintains both a focused beam width and angle invariably onto its integrated solar cells throughout the day. Computational and experimental studies at various incident angles prove the benefits of the design. Demonstrations of a custom‐built cylindrical lens solar tracker installed on a rooftop or sidewall of a building prove the feasibility of the proposed concept.