송현철 교수

Recent advances in lithography technology and the spread of 3D printers allow us a facile fabrication of special materials with complicated microstructures. The materials are called "designed materials" or "architectured materials" and provide new opportunities for material development. These materials, which owing to their rationally designed architectures exhibit unusual properties at the micro- and nano-scales, are being widely exploited in the development of modern materials with customized

We demonstrate a microscale vibration energy harvester exhibiting an ultra-low resonance frequency and high power density. A spiral shaped microelectromechanical system (MEMS) energy harvester was designed to harvest ambient vibrations at a low frequency (<;200 Hz) and acceleration (<;0.25 g). High quality Pb(Zr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.48</sub> Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w

Abstract Piezoelectric energy harvesters (PEHs) aim to generate sufficient power to operate targeting device from the limited ambient energy. PEH includes mechanical‐to‐mechanical, mechanical‐to‐electrical, and electrical‐to‐electrical energy conversions, which are related to PEH structures, materials, and circuits, respectively; these should be efficient for increasing the total power. This critical review focuses on PEH structures and materials associated with the two major energy conversions

(1− x )(Na 0.5 K 0.5 )NbO 3 – x LiNbO 3 [(1− x )NKN– x LN] ceramics were produced by the conventional solid‐state sintering method, and their microstructure and piezoelectric properties were investigated. The formation of the liquid phase and K 6 Li 4 Nb 10 O 30 second phase that were observed in the (1− x )NKN– x LN ceramics was explained by the evaporation of Na 2 O during the sintering. A morphotropic phase boundary (MPB) was observed in the specimens with 0.05&lt; x &lt;0.08. Promising piezo

Identifying reliable and sustainable sources of electricity is a significant challenge of the present time. However, most energy-generation mechanisms produce unavoidable low-grade waste heat as a byproduct while harvesting (or converting) electrical energy from conventional or renewable energy sources. Each year, over 60% of the primary energy is wasted as heat. Accordingly, considerable efforts are being made to convert this waste heat into usable electrical energy using diverse energy convers

A conventional energy harvester usually has narrow operational bandwidth, which makes it difficult to harvest energy with varying frequencies in the actual field. Herein, a nonlinear piezoelectric energy harvester with a coupled beam array is designed to broaden bandwidth and improve energy harvesting performance. The proposed harvester consists of a base, two elastic supports, and four piezoelectric beams with different natural frequencies. Due to the coupling effect caused by the two elastic s

Acoustic energy transfer using ferroelectrically augmented triboelectric receivers can efficiently deliver energy to implantable medical devices, marine cable operation sensors, and electronic devices with electromagnetic interference shielding cases.

Wireless energy transfer (WET) based on ultrasound-driven generators with enormous beneficial functions, is technologically in progress by the valuation of ultrasonic metamaterials (UMMs) in science and engineering domains. Indeed, novel metamaterial structures can develop the efficiency of mechanical and physical features of ultrasound energy receivers (US-ETs), including ultrasound-driven piezoelectric and triboelectric nanogenerators (US-PENGs and US-TENGs) for advantageous applications. This

Piezoelectric materials are a class of materials that can generate an electric charge when subjected to mechanical stress, or vice versa. These materials have a wide range of applications, from sensors and actuators to energy-harvesting devices and medical implants. Recently, there has been growing interest in using 3D printing to fabricate piezoelectric materials with complex geometries and tailored properties. Three-dimensional printing allows for the precise control of the material’s composit

Abstract Despite the rapid development of various wearable generators to harvest energy from human activity, they are limited to single or intermittent power generation. Here, stretchable and washable energy harvesting fabric is reported, which enables biomechanical and biochemical generation through co‐weaving triboelectric generator (TEG) and perspiration electric generator (PEG)‐based fibers. The two energy harvesting approaches can work individually or simultaneously, thereby combating humid