Precise synthesis of copper selenide nanowires with tailored Cu vacancies through photo-induced reduction for thermoelectric applications.

Nanostructuring in α-CuSe while optimizing carrier concentration holds the promise of realizing further high thermoelectric performance at near room temperature. Nevertheless, controlling the amounts of Cu vacancies, which work as acceptors, in nanostructures is considerably more intricate than in bulk materials. Hence, controlling the amounts of Cu vacancies while maintaining the α-phase and nanostructure shape poses a formidable challenge.

Donut-Shaped Stretchable Kirigami: Enabling Electronics to Integrate with the Deformable Muscle.

Electronic devices used to record biological signals are important in neuroscience, brain-machine interfaces, and medical applications. Placing electronic devices below the skin surface and recording the muscle offers accurate and robust electromyography (EMG) recordings. The device stretchability and flexibility must be similar to the tissues to achieve an intimate integration of the electronic device with the biological tissues.

A Theoretical study on the charge and discharge states of Na-ion battery cathode material, Na FePO F.

Na FePO F is a promising cathode material for a Na-ion battery because of its high electronic capacity and good cycle performance. In this work, first principle calculations combined with cluster expansion and the Monte Carlo method have been applied to analyze the charge and discharge processes of Na FePO F by examining the voltage curve and the phase diagram. As a result of the density functional theory calculation and experimental verification with structural analysis, we found that the most stable structure of Na FePO F has the P2 /b11 space group, which has not been reported to date.

Ultrastretchable Kirigami Bioprobes.

An ultrastretchable film device is developed that can follow the shape of spherical and large deformable biological samples such as heart and brain tissues. Although the film is composed of biocompatible parylene for the device substrate and metal layers of platinum (Pt)/titanium (Ti), which are unstretchable materials, the film shows a high stretchability by patterning slits as a "Kirigami" design. A Pt/Ti-microelectrode array embedded in 11 µm thick parylene film with 5 × 91 slits exhibits a film strain of ≈250% at 9 mN strain-force (0.