Pan Zeng

Abstract: Achieving all‐printed, low‐cost, and large area electronic devices poses challenging requirements in employing printing technologies and conductive materials for flexible and wearable heaters. In this work, fully printed, scalable, and patterned flexible heaters based on Ag fractal dendrites (FDs) are fabricated through straightforward screen printing technology. The Ag FDs possess low sheet resistance with ≈0.83 Ω sq−1 when sintered at low temperature of 60 °C. The Ag FDs are directly printed on thin polyethylene terephthalate substrate to manufacture flexible heaters, exhibiting excellent heating performance with the saturation temperature up to ≈135 °C and rapid response time within 35 s under 4 V DC voltage. In addition, the Ag FDs heaters present lower power consumption (≈209.67 °C cm2 W−1), which is significantly better than traditional indium tin oxides (ITO) heaters (≈88 °C cm2 W−1). The sheet resistance of the devices remains stable after 2000 bending cycles with a radius of 10 mm, indicating that the outstanding mechanize stability of the heaters. Moreover, a large area (12 cm × 5 cm) heater with designable pattern is developed and attached to human body, indicating a bright future in next‐generation fully printed and wearable heating electronics application.

TL;DR: Three kinds of core-triple-shell Ln3+ ions doped NaYF4 upconversion nanocrystals (UCNCs) are synthesized through modified high-temperature coprecipitation, which demonstrate excellent UPL properties of independent emitting colors under 808 or 980 nm laser excitation.

TL;DR: In this article, a flexible and stretchable conductor was fabricated by embedding fractal-structured silver particles in a PDMS substrate, which can stretch up to 100% and bend and twist up to 180°.