Physical Sensors & Devices

This work pertains to the multi-objective inverse design of impact-resistant metamaterials under varying strain rates. Impact-resistant materials are desirable in a wide range of applications, such as sports, automobiles, military, and aircraft, to name a few. Existing literature deals with refining these structures by performing quasi-static finite element (FE) simulations and then verifying them experimentally, which is a time-consuming and expensive process. Moreover, beyond the low-velocity regime, quasi-static simulations are not representative of real-world dynamic...

The rapid development of additive manufacturing technologies has enabled the fabrication of truss metamaterials, i.e., a novel class of lightweight-yet-strong materials with engineered complex hierarchical structures. Manipulating the architecture over chemical composition dramatically expands the achievable materials design space, allowing to largely control the mechanical response of metamaterials. Despite the great advances made in this area, designing three-dimensional (3D) truss metamaterials under complex or extreme conditions with programmable response is still a...

Tellurium is a narrow-gap, p-type semiconductor with promising potential for future electronic and optoelectronic devices. Te’s band gap can be tuned from 0.31 eV in bulk form to 1.04 eV in monolayer form. Unlike many other competing 2D semiconductors, Te is air-stable and can be deposited on a substrate of choice by thermal evaporation or solution synthesis. Photodetectors based on solution-synthesized Te nanoflakes have already been demonstrated, with specific detectivity in near-IR at or above 10^9 Jones. However, solution-synthesis of Te nanoflakes is not scalable, and...

We have been developing sweat sensors to analyze physiological and metabolic health information, such as sweat rate, glucose levels, pH, and various electrolytes, from any surface on the body surface where sweat glands are present. However, the stiff sweat sensors developed so far struggle to detect subtle signal changes, especially on soft skin. This is due to a mechanical mismatch between the rigid sweat sensor and the pliable skin, which can lead to motion artifacts and delamination of the patch from skin. Specifically, the stiff sensor cannot easily stretch along with the...