Ali Javey (Advisor)

Black phosphorus (BP) is a narrow bandgap layered semiconductor promising for mid-infrared optoelectronic applications. BP-based devices have been shown to surpass state-of-the-art mid-infrared detectors and light-emitting diodes (LEDs) in terms of performance. Despite their device advantages, the material’s inherent instability in the air could hinder its use in practical optoelectronic applications. Here, we investigated the impact of passivation on the device lifetime of BP LEDs, which deteriorate in a matter of seconds without using passivation. The lifetime is significantly extended...

In the field of sweat monitoring, many sensors have been piloted with one or two subjects over limited periods of time, but there is a need for prolonged, large-scale studies to establish reliable physiological correlations that account for diverse subjects, activities, and environments. Chemical sensors provide the concentration of analytes of interest, including sodium, potassium, and glucose, while sweat rate sensors provide standalone information on nerve function and hydration. Monitoring both of these in parallel will enable the decoding of concentrations of analytes that are...

Wearable sweat sensors have emerged as attractive platforms for non-invasive health monitoring. While most sweat sensors have relied on exercise or chemical stimulation to generate sweat, natural thermoregulatory sweat is an attractive alternative as it can be accessed during routine and even sedentary activity without impeding user lifestyles, while also potentially preserving correlations between sweat and blood biomarkers. For rapid accumulation of natural sweat that enables quick, single-point measurement of sweat analytes, we develop a simple, skin-attachable sensing platform to...