Saurabh Pandey

In emerging technologies such as smartphones and smart windows, flexible and transparent miniaturized energy storage systems are essential, yet existing devices often fail for practical applications. To address this, a plasmon-assisted strategy is employed to enhance microsupercapacitor (MSC) performance by incorporating silver nanowires into a ZnO-based transparent device on a flexible polydimethylsiloxane (PDMS) substrate. The MSC exhibits outstanding electrochemical performance, achieving a volumetric capacitance of 996.73 F cm^–3, an energy density of 138.43 mWh cm^–3, and a power density of 1.74 W cm^–3 under combined plasmonic excitation and photoirradiation, ∼50% enhancement relative to the dark condition. The silver nanowires act as plasmonic hot spots that promote redox activity through plasma induced resonance energy transfer (PIRET), which is also confirmed by finite-difference time-domain (FDTD) simulations. The platform harvests sunlight and hydrovoltaic energy to power an LED for 90 s, demonstrating potential for next-generation flexible, transparent microscale energy storage systems.

This study presents a cost-effective approach to implement the guided mode resonance (GMR) sensors for refractive index (RI) measurements. A silicon nitride (Si₃N₄) GMR chip, fabricated using e-beam lithography and incorporating an in-house diffraction grating, is integrated with a low-cost CMOS sensor for optical readout. This system effectively detects variations in the GMR output corresponding to RI changes. Experimental results demonstrate a sensitivity of 2.02 mm RIU⁻¹, derived from the linear regression slope of the CMOS intensity spot position against RI variations. This innovative combination of GMR and CMOS technologies not only reduces costs but also significantly simplifies the detection mechanism, opening new possibilities for optical sensing applications.

Flexible capacitive sensors are gaining popularity in place of sophisticated optical sensing or bulky mechanical designs for specific applications such as proximity/gesture detection and liquid level sensing. So, here, we propose Laser Induced Graphene Foam (LIGF) based planar capacitive sensors, which are flexible, highly sensitive, energy-efficient, and cost-effective, making them accessible for various applications. The working of these sensors involves the interdigitated planar electrode configuration and the fringing effect, influencing capacitance when the permittivity or the electric charge of the surrounding medium changes. LIGF planar capacitive elements were produced on a commercially availed polymer polyimide by using direct laser writing technique employing a low-cost diode laser. The developed LIGF-based planar capacitive touch sensor showed an average touch response (|ΔC/Co|) of more than 49%; moreover, when used for proximity sensing, this sensor could detect the presence of human hand up to a maximum distance of 170 mm from the sensor surface. An extended design of the sensor has demonstrated liquid level sensing with an accuracy of 0.97 mm. As a result of its ability to sense dielectric materials, contactless operation, long-range sensing, cost-effectiveness, low-power consumption, and environmental friendliness, the LIGF electrode-based capacitive sensor can be incorporated into a variety of modern technology and devices.