BITS Faculty Publications
Permanent URI for this communityhttp://localhost:4000/handle/123456789/1867
Browse
95 results
Search Results
Item Investigation on substrate material for a sensitive flexible piezoresistive pressure sensor(IEEE, 2025-02) Gupta, NavneetThis study investigates the substrate in flexible piezoresistive pressure sensor (FPPS) for improving the performance of sensors. Initially, we employed the technique for order preference by similarity to ideal solution (TOPSIS) and VlseKriterijumska Optimizacija I Kompromisno Resenjein in Serbian (VIKOR) to evaluate all potential substrates materials for FPPS. Key material attributes that play an important role are the glass transition temperature, thermal conductivity, Young’s modulus, water absorption, and coefficient of thermal expansion (CTE). To identify the most promising substrate material, we utilized the TOPSIS and VIKOR ranking systems followed by simulation analysis using COMSOL Multiphysics 6.0. Our analysis shows that polyethylene naphthalate (PEN) is the optimal substrate material for FPPS. The results demonstrate good agreement across all material selection methodologies and simulations, validating the robustness of our findings.Item Design and enhancing performance of lead-free flexible perovskite solar cells: a numerical approach(IEEE, 2025-02) Gupta, NavneetLead-free perovskite materials have emerged as the most feasible option for photovoltaics to address the issue of toxicity and better performance. This study aims to design and enhance the performance of lead-free methylammonium (MA) and formamidinium (FA) compound (FAMASnGeI3)-based flexible perovskite solar cell (FPSC) by utilizing the solar cell capacitance simulator 1-D (SCAPS-1D). The optimization of various geometrical parameters and charge densities of the absorber and charge transport layers show the improvement in power conversion efficiency (PCE). We have obtained Voc of 0.87V, Jsc of 45.7 mA/cm2, fill factor (FF) of 75.3%, and PCE of 29.9%. The obtained results were compared with similar existing research based on various absorber layers. It was found that the selected absorber layer improves the performance of FPSCs.Item Design and simulation of energy efficient OLEDS for flexible electronics applications(IEEE, 2025-05) Gupta, NavneetOrganic Light Emitting Diodes (OLEDs) are a promising technology known for their thin, energy-efficient, and high-quality light emission, making them ideal for displays and lighting applications. Flexible OLEDs, an emerging development from conventional rigid OLEDs, can be integrated into curved or bendable surfaces, enabling new design possibilities in wearable electronics, foldable screens, and innovative lighting solutions. In this work, we designed and simulated a multilayer OLED structure using TCAD (Technology Computer-Aided Design) software, focusing on material selection for the emission layer to optimize energy efficiency and performance. Three candidate materials—Alq3, PPV, and PFO—were evaluated, with PFO demonstrating superior luminescent power and energy efficiency. Through geometry optimization of the PFO layer, we achieved an energy efficiency of 14.08%, highlighting its potential as a suitable alternative to Alq3 for flexible OLED applications.Item Optimizing material choices for flexible pressure sensors driven by triboelectric nanogenerators(IEEE, 2025-04) Gupta, NavneetThis study shows the investigations on optimal dielectric material for self-powered flexible pressure sensors (SPFPSs) based on triboelectric nanogenerators (TENGs) using multiple criteria decision-making (MCDM) methods. Specifically, we utilized technique for order preference by similarity to ideal solution (TOPSIS) and VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) techniques to identify potential dielectric materials. Several materials attributes, such as surface charge density, coefficient of friction, and dielectric constant, are examined to find out the best dielectric material. Through the TOPSIS and VIKOR ranking systems, we determined that polydimethylsiloxane (PDMS) is the most suitable dielectric material for TENG-based SPFPSs. The result presents a strong alignment across material selection methods and simulations that validates the robustness of our proposed outcomes.Item Flexible CPW-Fed antenna for ultra-wideband wearable application(IEEE, 2025-03) Gupta, Navneet; Deepa, P.R.This paper introduces a compact, slotted coplanar waveguide (CPW)-fed antenna that exhibits a wide bandwidth (fractional bandwidth >50%) within the ultra-wideband (UWB) range, and is also flexible. The antenna design features hexagonal rings that are cut and slotted on a polydimethylsiloxane (PDMS) substrate to achieve these characteristics. The slotted hexagonal ring radiator is fed by a tapered CPW, positioned centrally on a trapezium-shaped ground plane. The antenna operates effectively over a frequency range of 1.68 to 9.03 GHz, achieving a total impedance bandwidth of 7.35 GHz (S11<−10 dB for 1.68−9.03GHz, VSWR <2). The peak gain across the band is 6.71 dBi. Through various design iterations, the peak gain is observed to be 6.71 dBi at 6.5 GHz and 4.07 dBi at 2.4 GHz. Additionally, the antenna maintains an axial ratio (AR)<3 dB from 1.75 to 1.83 GHz, and a specific absorption rate (SAR) of 1.33 W/kg for 1 g of tissue. The overall dimensions of the antenna are 95×80 mm2.Item Flexible and Wearable Sensors for Health Monitoring Applications(CRC Press, 2023) Gupta, NavneetOver the past decade, flexible electronics have attracted much interest as conventional semiconductors are not competent to provide new product paradigms. The flexible devices are bendable, stretched, and can be folded without losing functionality. Flexible electronics devices are used in various fields, such as consumer electronics, medical, health care, and security devices, because they are generally lightweight, non-breakable, and involve a relatively simple manufacturing process. The use of wearable electronics for non-invasive real-time health monitoring has also gained popularity. The continuous monitoring of body locomotion, biophysical parameters, and biomarkers is valuable in quantifying human performance and off-site patient care. Flexible electronics provide a natural interaction between the human body and wearable devices because of their high flexibility and conformity. So, in this chapter, we shall discuss the flexible substrate, active material, transduction mechanism, and fabrication processes of different flexible sensors with a special focus on temperature, pressure, and strain sensors.Item Microheater Material Selection Framework for Micro-Electromechanical System (MEMS)-Based Gas Sensor(IEEE, 2023-09) Gupta, NavneetThis article describes the material selection for microheater in micro-electromechanical systems (MEMS)-based gas sensors. The analysis was done using multicriteria decision-making (MCDM) approaches: Ashby’s technique, Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), and VlseKriterijumska Optimizacija I Kompromisno Resenjein in Serbian (VIKOR). All possible materials for heating element used in MEMS gas sensors are considered. Various material properties, such as thermal expansion, melting point, resistivity, and thermal conductivity, are investigated to find out the most promising microheater material. Analysis was done using materials chart in Ashby’s approach and ranking system using TOPSIS and VIKOR approaches. The analysis shows that tungsten and molybdenum are the best materials to be used in microheater. The results show very good agreement among all the three material selection methodologies that confirms the validity of our proposed result.Item Silicone/Graphene Nanoplatelets based Flexible Strain Sensor for Wearable Electronics(IEEE, 2024-01) Gupta, NavneetThis study presents the development of strain sensors using two silicone rubbers (Ecoflex and polydimethylsiloxane) with graphene nanoplatelates (GNP). The polymer and graphene nanoplatelets capitalize on the elasticity of polymer and the electrical conductivity of GNP, making it for enhanced electrical response. This work presents the fabrication, characterization, and performance of both flexible strain sensors, elucidating their mechanical behavior and sensing capabilities by unifying flexibility, conductivity, and responsiveness. Both sensors displayed flexibility and linear change in resistance, highlighting their sensitivity. Comparative analysis revealed the Ecoflex/GNP sensor’s higher gauge factor, indicating elevated sensitivity for strain detection. The proposed Ecoflex/GNP and PDMS/GNP-based strain sensors are suitable for wearable electronics applications.Item Multiwall Carbon Nanotube/Polydimethylsiloxane Composites-Based Dry Electrodes for Bio-Signal Detection(IEEE, 2024-02) Gupta, NavneetContinuous, stable, and long-term monitoring of bio-signals, such as electrocardiogram (ECG) and electromyography (EMG), are utmost important in healthcare sector. In this work, we developed a multiwall carbon nanotubes (MWCNTs)/polydimethylsiloxane (PDMS) composites based bio-electrodes using a simple, low-cost, and solution-process method. The fabricated MWCNTs/PDMS composites electrode exhibited comparable electrode–skin impedance to conventional silver/silver chloride (Ag/AgCl) electrodes over the frequency range of 20 Hz–1 kHz. In addition, our developed electrodes has the ability to be applied on the skin in dry form without needing an intermediate gel layer or skin preparation. The results show that the MWCNT-/PDMS-based dry electrodes were efficient to acquire a real-time ECG signals. The fabricated electrodes showed better performance compared to the commercially available Ag/AgCl electrode in ECG and EMG measurements. The obtained results shows that the proposed dry bio-electrodes has a promising application in electronic/mobile health applications and wearable health monitoring applications.Item Flexible Silicon: Status, Opportunities, and Challenges(IEEE, 2024-09) Gupta, NavneetThe rise of the Internet of Everything has spurred the need for flexible and stretchable electronic devices, particularly in biomedical applications. Monocrystalline silicon, a key material in the semiconductor industry, must be adapted to meet these demands. This article explores various thinning techniques to fabricate flexible silicon wafers, methods for transferring silicon to flexible substrates, and the importance of enhancing silicon’s stretchability. Furthermore, it discusses the impact of flexible silicon on sectors such as biomedical sensing, electronics, and power systems, highlighting the role of the Internet of Things (IoT) platform in interconnecting devices. Finally, the article examines current progress and future prospects in flexible silicon technology, paving the way for further advancements in this rapidly evolving field.