In the past several years, research in soft and flexible electronics has promised to yield developments in wearable technology, including health and fitness monitoring tools, independence and mobility aids for the disabled, and human-computer interfaces for virtual and augmented reality. However, as these devices become thinner and lighter, they demand efficient power supplies with similar mechanical properties. Organic photovoltaics (OPVs)--known for their high flexibility, lightweight, and scalable fabrication methods-have recently attained power conversion efficiencies of over 17% and are excellent candidates to power these next-generation wearable devices. In this paper, we discuss recent developments in flexible OPVs, including advances in materials, structure, and integration with additional wearable components, such as sensors and displays. In addition, we describe our recent work in developing a self-powered actuator for a tactile feedback system.

Flexible electronics have attracted much attention since they enable promising applications such as low-cost RFID tags and e-paper. Thin-film transistors (TFTs) are considered as an ideal candidate to implement flexible electronics on low-cost substrates. Most TFT technologies, however, have only mono-type - either n- or p-type - devices and thus modern design technologies for silicon-based electronics cannot be directly applied. In this paper, we propose a novel design style Pseudo-CMOS for flexible electronics that uses only mono-type TFTs while achieving comparable performance with the complementary-type designs. The manufacturing cost and complexity can therefore be significantly reduced while the circuit yield and reliability are also enhanced with the built-in capability of post-fabrication tuning. Some standard cells have been designed and fabricated in p-type organic and n-type InGaZnO (IGZO) TFT technologies which successfully verify the superiority of the proposed Pseudo-CMOS design style. To the best of our knowledge, this is the first design solution that has proven superior performance for both types of TFT technologies.