Flexible solar cells have received growing attention recently because of their ever-increasing range of applications. Here, the development of ultraflexible, lightweight, and high efficiency (19%) monocrystalline silicon solar cells with excellent reliability, mechanical resilience, and thermal performance is demonstrated by applying a corrugation method combined with laser patterning. The flexing mechanism converts large-scale rigid photovoltaic cells with interdigitated back contacts (IBCs) into a flexible version with a preserved efficiency. The corrugation technique is based on the formation of patterned grooves in active silicon to achieve ultraflexibility. As a result, islands of silicon with different shapes are obtained which are interconnected through the IBCs. Multiple corrugation patterns such as linear, honeycomb, and octagonal designs are studied, each resulting in different flexing capabilities in terms of flexing directionality and minimum bending radius, in addition to providing an atypical appearance with an aesthetic appeal. The corrugation method is shown to improve thermal dissipation (14.6% lower temperature) and to relieve the thermal mismatch challenge compared to the rigid cells because of the finlike architecture. Finally, encapsulation using a transparent polymeric material enables a robust performance of the flexible cells when exposed to different environmental conditions such as acid rain, snow, and mechanical shocks.

The epitaxial growth of technically-important β-Ga2O3 semiconductor thin films have not been realized on flexible substrates due to limitations by the high-temperature crystallization conditions and the lattice-matching requirements. In this report, for the first time single crystal β-Ga2O3 (-201) thin films is epitaxially grown on the flexible CeO2 (001)-buffered hastelloy tape. The results indicate that CeO2 (001) has a small bi-axial lattice mismatch with β-Ga2O3 (-201), thus inducing a simultaneous double-domain epitaxial growth. Flexible photodetectors are fabricated based on the epitaxial β-Ga2O3 coated tapes. Measurements show that the obtained photodetectors have a responsivity of 40 mA/W, with an on/off ratio reaching 1000 under 250 nm incident light and 5 V bias voltage. Such photoelectrical performance is already within the mainstream level of the β-Ga2O3 based photodetectors by using the conventional rigid single crystal substrates; and more importantly remained robust against more than 1000 cycles of bending tests. In addition, the epitaxy technique described in the report also paves the way for the fabrication of a wide range of flexible epitaxial film devices that utilize the materials with lattice parameters similar to β-Ga2O3, including GaN, AlN and SiC.

Motion sensors are an essential component of many electronic systems. However, the development of inertial motion sensors based on fatigue-free soft proof mass has not been explored extensively in the field of soft electronics. Nontoxic gallium-based liquid metals are an emerging class of material that exhibit attractive electromechanical properties, making them excellent proof mass materials for inertial sensors. Here, we propose and demonstrate a fully soft laser-induced graphene (LIG) and liquid metal-based inertial sensor integrated with temperature, humidity, and breathing sensors. The inertial sensor design confines a graphene-coated liquid metal droplet inside a fluidic channel, rolling over LIG resistive electrode. The proposed sensor architecture and material realize a highly mobile proof mass and a vibrational space for its oscillation. The inertial sensor exhibits a high sensitivity of 6.52% m −1 s 2 and excellent repeatability (over 12 500 cycles). The platform is fabricated using a scalable, rapid laser writing technique and integrated with a programmable system on a chip (PSoC) to function as a standalone system for real-time wireless monitoring of movement patterns and the control of a robotic arm. The developed printed inertial platform is an excellent candidate for the next-generation of wearables motion tracking platforms and soft human− machine interfaces.

aquaculture grew to compensate for the reduced fish abundance due to the overfishing in the wild fisheries. [3] Currently, aquaculture provides more than 50% of the globally consumed fish, and during the last 10 years, the yearly global returns for fish farming grew from $60 billion to more than $231.6 billion. The corresponding total production is more than 80 million tonnes of fish. [1] Nevertheless, water pollution in the ponds is considered as the major cause of financial losses in the market especially in the rapidly urbanizing areas. For instance, the aquaculture in China suffered from a $1 billion loss in 2010 due to water pollution and consequent fish death. [4] Pollution in ponds water can be due to biological, chemical, and atmospheric reasons, all of which are inter-related, leading to the reduction in fish yield. For instance, the increased nutrient concentration in the ponds due to fertilizers, pesticides, or increased urbanization and resultant industrial waste with high amounts of phosphates and nitrogen result in a phytoplankton and algal heavy bloom. [5] When the algae is decomposing, it excretes toxic levels of ammonia and consumes the oxygen in the water resulting in fish asphyxia. Human agricultural activities can also increase the heavy metals and salts concentration in ponds to reach toxic levels. Moreover, the quality of the air surrounding the pond greatly contributes to the water quality where high levels of sulfur oxides and nitrogen oxides generated from combustion of fossil fuels and transportation can either dissolve or deposit on the surface of the water, leading to the deterioration of the water quality. [6,7] Hence, preventive measures can be taken by the farmers to protect the fishes when toxic levels of air pollutants are detected. Other key factors that affect the fish production are the sunlight exposure and the temperature of the water. Sunlight is critical for the regulation of the water temperature-a too high temperature reduces the density of oxygen while a too low temperature reduces the fish metabolism-and for the production of the natural food in the ponds-plankton and photosynthesis. [8,9] Therefore, real-time monitoring of water quality is essential for protecting and further fostering the aquaculture industry growth.Among major food production sectors, world aquaculture shows the highest growth rate, providing more than 50% of the global seafood market. However, water pollution in fish farming ponds is regarded as the leading cause of fish death and financial losses in the market. Here, an Internet of Things system based on a cubic multidimensional integration of circuit (MD-IC) is demonstrated for water and food security applications in fish farming ponds. Both faces of the silicon substrate are used for thin-film-based device fabrication. The devices are interconnected via through-silicon-vias, resulting in a bifacial complementary metal-oxide-semiconductor-compatible electronics system. The demonstrated cubic MD-IC is a complete, small, and lightweight system that ...

Accelerometers are among the most mature sensor technologies with a broad range of applications in multiple fields and industries. They represent the most widely used microelectromechanical system (MEMS) devices with excellent and reliable performance. MEMS acceleration sensors established dominance mainly in navigation and control applications. In recent years, however, recent technologies and materials have emerged that introduce novel sensing mechanisms, improve performance, enable customization, reduce cost, and reduce fabrication complexity. Herein, the recent advances in accelerometers based on MEMS and recent emerging technologies are reviewed. This work provides a comprehensive review of accelerometers' sensing mechanisms and the main characteristics and features of each type of sensor, material, and fabrication strategies used to fabricate them. From the aspect of sensor application, this work focuses on reviewing applications that demonstrate the use of accelerometers manufactured using unconventional technologies and materials in prevailing fields such as healthcare monitoring, automotive industry, navigation, building, and structural monitoring. Moreover, challenges and future efforts needed to be addressed in this field are summarized.