Fuel cell application to mitigate load ramping impacts of rooftop pv system installation

This paper is based on a hybrid PV and fuel cell system designed to meet energy requirements of 100000 customers of Southern California in a sustainable way. Solar roof-top PV system is turning out to be a boon to the mankind with its positive effects of reducing Green House Gas (GHG) emission, lowering stress on conventional coal-fired or natural gas generators and even reducing costs associated with electricity pricing for consumers. However, with increased penetration from the grid tied PV systems, there is an inevitable rise in stress faced by conventional generators in terms of meeting and balancing the energy requirements during early morning and late afternoon hours which requires precise switching and control mechanisms. This paper addresses the ramping issues and offers an integrated solution in the form of fuel cells that can complement the existing PV system during intermittent times of energy production and even by reducing the ramp up and ramp down slopes of power production by conventional generators, in a promising way.Published versio

Advanced low‐dimensional carbon materials for flexible devices

We live in a digitized era, where we are completely surrounded by a plethora of automated electronic systems, be it a smart home energy controller or a self‐operated diagnostic kiosk in a clinic. With the recent advent of one‐dimensional (1D) and two‐dimensional (2D) nanomaterials like carbon nanotube (CNT) and graphene, the world of electronics has revolutionized with state‐of‐the‐art product paradigms. These nanomaterials possess desirable features of large surface area, excellent electrical conductivity, and high mechanical strength. Electronic devices made out of these materials have the added advantages of being flexible, light‐weight, and durable. Thus, present‐day devices that utilize these substances as channel or electrode materials have been able to undergo a positive transformation as compared with conventional structures. Flexibility and bendability are some of the coveted aesthetics of modern‐day electronics and the use of these 1D and 2D nanomaterials imparts such features to the devices, without having to compromise on key output characteristics like sensitivity and efficiency. In this short review, we discuss about various new configurations that are based on graphene, CNT, and other materials like transition metal dichalcogenides, and how these materials have been able to metamorphose the attributes of conventional devices.NRF (Natl Research Foundation, S’pore)Published versio

Multifaceted Hybrid Carbon Fibers: Applications in Renewables, Sensing and Tissue Engineering

The field of material science is continually evolving with first-class discoveries of new nanomaterials. The element carbon is ubiquitous in nature. Due to its valency, it can exist in various forms, also known as allotropes, like diamond, graphite, one-dimensional (1D) carbon nanotube (CNT), carbon fiber (CF) and two-dimensional (2D) graphene. Carbon nano fiber (CNF) is another such material that falls within the category of CF. With much smaller diameters (around hundreds of nanometers) and lengths in microns, CNFs have higher aspect (length to diameter) ratios than CNTs. Because of their unique properties like high electrical and thermal conductivity, CNFs can be applied to many matrices like elastomers, thermoplastics, ceramics and metals. Owing to their outstanding mechanical properties, they can be used as reinforcements that can enhance the tensile and compressive strain limits of the base material. Thus, in this short review, we take a look into the dexterous characteristics of CF and CNF, where they have been hybridized with different materials, and delve deeply into some of the recent applications and advancements of these hybrid fiber systems in the fields of sensing, tissue engineering and modification of renewable devices since favorable mechanical and electrical properties of the CFs and CNFs like high tensile strength and electrical conductivity lead to enhanced device performance

Heterolayered films of monolayer WS2 nanosheets on monolayer graphene embedded in poly(methyl methacrylate) for plasmonic biosensing

International audienceThe interplay between light photons and nanomaterials can give rise to many striking phenomena. Surface plasmon resonance (SPR), which is one such plasmonic sensing mechanism, is gaining much attention from the biomedical fraternity. Two-dimensional (2D) nanomaterials like transition-metal dichalcogenides (TMDCs) and graphenes are recently discovered nanomaterials that have favorable properties like high optical absorption. These materials have been applied extensively in the fields of drug delivery and cancer therapy. However, their applications in the area of plasmonic biosensing need to be explored more. Hence, using commercial SPR sensors, we demonstrate the effectiveness of heterostructured monolayer nanosheets of graphene and WS2 for a plasmonic-based detection system of a specific ligand-analyte interaction between bovine serum albumin (BSA) and anti-BSA. Our detection technique does not require any complex functionalization scheme as the graphene-WS2 nanosheet-coated gold chip can attach protein molecules through hydrophobic interactions. The limit of detection (LOD) obtained for the anti-BSA protein is 0.44 μg/mL

Investigation of plasmonic detection of human respiratory virus

The COVID-19 virus has been recently identified as a new species of virus that can cause severe infections such as pneumonia. The sudden outbreak of this disease is being considered a pandemic. Given all this, it is essential to develop smart biosensors that can detect pathogens with minimum time delay. Surface plasmon resonance (SPR) biosensors make use of refractive index (RI) changes as the sensing parameter. In this work, based on actual data taken from previous experimental works done on plasmonic detection of viruses, a detailed simulation of the SPR scheme that can be used to detect the COVID-19 virus is performed and the results are extrapolated from earlier schemes to predict some outcomes of this SPR model. The results indicate that the conventional Kretschmann configuration can have a limit of detection (LOD) of 2E-05 in terms of RI change and an average sensitivity of 122.4 degRIU−1 at a wavelength of 780 nm.National Research Foundation (NRF)This work was supported by the Singapore National Research Founda-tion (NRF) and French National Research Agency (ANR), grant number(NRF2017-ANR002 2DPS)

Gold nanorod assisted enhanced plasmonic detection scheme of COVID-19 SARS-CoV-2 spike protein

The beautiful interplay between light and matter can give rise to many striking physical phenomena, surface plasmon resonance (SPR) being one of them. Plasmonic immunosensors monitor refractive index changes that occur as a result of specific ligand–analyte or antibody–antigen interactions taking place on the sensor surface. The coronavirus disease (COVID-19) pandemic has jeopardized the entire world and has resulted in economic slowdown of most countries. In this work, a model of a sandwich plasmonic biosensor that utilizes gold nanorods (Au NRs) for the detection of COVID-19 SARS-CoV-2 spike protein is presented. Simulation results for different prismatic configurations for the basic Kretschmann layout are presented. It is found that a BK7 glass prism-based SPR sensor has an incremental sensitivity of 111.11 deg RIU−1. Additionally, using Comsol Multiphysics the electric field enhancement observed for various aspect ratios and layouts of Au NRs are discussed in depth.Nanyang Technological UniversityNational Research Foundation (NRF)This work was supportedby the National Research Foundation (NRF) Singapore and French Na-tional Research Agency (ANR), Grant No. (NRF2017–ANR002 2DPS) andProvost’s Chair in Electrical and Electronic Engineering Award (002354–00001)

In-Depth Conceptual Study of an Enhanced Plasmonic Sensing System Using Antireflective Coatings and Perovskites for the Detection of Infectious Viral Antigens

Since its beginning, various countries have gone through multiple waves of surging COVID-19 infections. With the emergence of variants like Delta and Omicron, the disease is highly contagious and has the ability to spread at an alarming rate. In such scenarios, a quick and effective detection system is highly desirable. In this study, we present the concept of a surface plasmon resonance (SPR) based sensing system that can be utilized efficiently and reliably for the detection of SARS-CoV-2 antigens. The SPR system offers multiple advantages like real-time and label-free sensing of analytes and commercial systems have been in the market for more than two decades. Antireflective coatings (ARCs) have a number of application areas because of their unique properties. But they have seldom been used in the area of SPR sensing Hence, with the help of simulation, we make use of these coatings as intermediate layers and propose an enhanced sensing scheme by making use of ARCs of TiO2 and SiO2 and perovskite materials BaTiO3, PbTiO3, and SrTiO3. We found that, using TiO2, SiO2, and PbTiO3, a maximum sensitivity of 392 degRIU-1 can be obtained which is 5.29-fold enhancement as compared to the standard SPR arrangement using gold

Label-free plasmonic-based biosensing using a gold nanohole array chip coated with a wafer-scale deposited WS₂ monolayer

This paper reports the fabrication, testing and obtained performance of a plasmonic sensor employing a gold (Au) nanohole array chip coated with tungsten disulphide (WS2), which is then functionalized for the detection of protein-protein interactions. A key novelty is that the WS2 was deposited as a monoatomic layer using a wafer-scale synthesis method that successfully provided a film of both high quality and uniform thickness. The deposited WS2 film was transferred onto a Au nanohole array chip using a novel method and was subsequently functionalized with biotin. The final sensor was tested and it demonstrated efficient real-time and label-free plasmonic detection of biotin-streptavidin coupling. Specifically, compared to a standard (i.e. uncoated) Au nanohole-based sensor, our WS2-coated Au nanohole array boosted the spectral shift of the resonance wavelength by ∼190%, resulting in a 7.64-fold improvement of the limit of detection (LOD).National Research Foundation (NRF)Submitted/Accepted versionThis work was supported by the Singapore National Research Foundation (NRF) and French National Research Agency (ANR), grant number (NRF2017–ANR002 2DPS)

Electrically tunable singular phase and Goos–Hänchen shifts in phase-change-material-based thin-film coatings as optical absorbers

The change of the phase of light under the evolution of a nanomaterial with time is a promising new research direction. A phenomenon directly related to the sudden phase change of light is the Goos-Hänchen (G-H) shift, which describes the lateral beam displacement of the reflected light from the interface of two media when the angles of incidence are close to the total internal reflection angle or Brewster angle. Here, an innovative design of lithography-free nanophotonic cavities to realize electrically tunable G-H shifts at the singular phase of light in the visible wavelengths is reported. Reversible electrical tuning of phase and G-H shifts is experimentally demonstrated using a microheater integrated optical cavity consisting of a dielectric film on an absorbing substrate through a Joule heating mechanism. In particular, an enhanced G-H shift of 110 times of the operating wavelength at the Brewster angle of the thin-film cavity is reported. More importantly, electrically tunable G-H shifts are demonstrated by exploiting the significant tunable phase change that occurs at the Brewster angles, due to the small temperature-induced refractive index changes of the dielectric film. Realizing efficient electrically tunable G-H shifts with miniaturized heaters will extend the research scope of the G-H shift phenomenon and its applications.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)National Research Foundation (NRF)Accepted versionK.V.S. and R.S. acknowledge the funding support from Singapore Ministry of Education (MOE) grant numbers AcRF MOE2016-T3-1-006 and MOE AcRF Tier 1 RG96/19 and Advanced Manufacturing and Engineering (AME) Programmatic grant (A18A5b0056) by Agency for Science, Technology and Research (A*STAR). R.M. and R.S.R. would like to acknowledge the Ministry of Education (MOE) through Tier 2 grants (2019-T2-1-058). In addition, C.M.D. and K.T.Y. acknowledge the funding support from Singapore National Research Foundation (NRF) and French National Research Agency (ANR), grant number (NRF2017-ANR002 2DPS)