#thermoelectric

(Nanowerk News) Wireless charging is nothing new for our phones, watches, earbuds, and other tech. Now, researchers want to bring wireless power to the skies—recharging drones mid-flight by beaming a laser under their wings. Reporting in Matter & Light ("Sb2Se3 nanocrystals enable efficient perovskite-thermoelectric tandem devices for laser-powered unmanned aerial vehicles"), researchers engineered a lightweight receiver based on solar cell design that captures energy from a laser beam and turns it into electricity. To keep the device cool, the researchers strategically placed it on the wings of a drone and utilized heat-blocking technology, allowing the receiver to convert more of the laser’s energy into usable power.

Credit: Candler Hobbs, Georgia Tech

Researchers at the Georgia Institute of Technology, USA, have demonstrated proof-of-concept wearable thermoelectric generators that can harvest energy from body heat to power simple biosensors for measuring heart rate, respiration or other factors using flexible conducting polymers and novel circuitry patterns printed on paper.

The devices can be cut to the size needed to provide the voltage and power requirements for specific applications due to their symmetrical fractal wiring patterns. The modular generators could be inkjet printed on flexible substrates, including fabric, and manufactured using inexpensive roll-to-roll techniques.

The devices have thousands of dots composed of alternating p-type and n-type polymers in a closely-packed layout. Their pattern converts more heat per unit area due to large packing densities enabled by inkjet printers. By placing the polymer dots closer together, the interconnect length decreases, which lowers the total resistance and results in a higher power output from the device.

Candle Powered Lamp

Collective vibrations unlock fast ion flow in superionic crystals

In the race to develop safer, faster-charging solid-state batteries and more efficient thermoelectric conversion technologies, engineers and scientists have long faced a fundamental challenge: how to ensure ions move through hard, solid materials as quickly as they do in liquids? A team led by Prof. Zhou Yanguang, Associate Professor in the Department of Mechanical and Aerospace Engineering (MAE) at The Hong Kong University of Science and Technology (HKUST), discovered a novel mechanism for rapid ion transport in solids, opening new avenues for materials design. The study shows that the ionic transport is governed by collective dynamics. The results were published in the journal Physical Review Letters, titled "Fast Ionic Transport Governed by Collective Vibrational Dynamics."

Unusual nonlinear thermoelectric effect appears in chiral tellurium, confirming theoretical predictions

An unusual thermoelectric effect has been observed in the semiconductor tellurium by RIKEN physicists for the first time. This demonstration points to the potential of similar materials to be used in applications such as energy harvesting and advanced heat management. Thermoelectric materials can convert electricity into heat and vice versa. For most of them, doubling the voltage across them will double the heat they produce. But for some special thermoelectric materials, there is a nonlinear relationship between voltage and heat. Such nonlinear thermoelectric materials are useful for applications that require heat to flow in one direction and for generating electricity from thermal fluctuations. Some theoretical calculations have predicted that even more exotic nonlinear thermoelectric effects will occur in materials where the atoms or molecules have a chiral arrangement. But they hadn't been observed in the lab—until now.

Defect engineering lifts chalcopyrite thermoelectrics to record performance

A research team led by Prof. Zhang Jian at the Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, in collaboration with Prof. Xiao Chong from the University of Science and Technology of China and Prof. Zhang Yongsheng from Qufu Normal University, achieved a peak ZT value of 2.03 at 873 K in chalcopyrite-based thermoelectric materials using a novel dual antisite defect strategy. Their findings are published in the Journal of the American Chemical Society. In this study, the researchers developed a new Ag/In alloying strategy to introduce dual antisite defects in the Cu0.7Ag0.3Ga1-xInxTe2 thermoelectric system. These defects occurred when certain atoms swapped positions in the crystal lattice, and they helped decouple the thermal and electrical transport processes. This allowed the material to conduct electricity more efficiently while blocking heat, overcoming a common challenge in thermoelectric design, where improving one property often compromised another.