Decrease In Lifetime Research Articles

Tracing the Origins of Calendar Aging in Si-Containing Lithium-Ion Batteries.

Lithium-ion batteries (LIBs) with silicon/graphite composite (Si/C) anodes are still facing the challenge of unsatisfactory calendar life, and the specific impact of Si on this issue is largely unknown. Herein, the calendar aging behaviors are quantified across scales and explored in a top-down manner. Batteries with 10 wt % Si/C anodes suffer a 4-fold decrease in the overall lifetime and a 4-5-fold increase in irreversible anode loss. Significant parasitic reactions and solid electrolyte interphase growth occur after 72 h of storage with an oxygen increase of 1.3 times on the anode surface and 26 times in the interphase. The micromorphology and component are analyzed in detail, highlighting remarkable Li2CO3 precipitation. Finally, the impact on calendar aging is discussed in both external conditions and internal components. Mitigating the electrolyte decomposition caused by active Si will be key to improving the battery's calendar life.

Temperature Dependent Optical Properties of Ultrathin InAs Quantum Well

Temperature-dependent photoluminescence (TDPL) and time-resolved photoluminescence (TRPL) of ultrathin InAs quantum wells (QWs) in GaAs matrix have been investigated to understand the optical properties of carriers. Samples containing different thicknesses of InAs (0.5, 0.75, 1, 1.2, 1.4 monolayers) have been used for this study. The PL peak position of InAs with temperature does not follow the Varshni model at low temperatures. The activation energy (EA) of these QWs has been calculated from TDPL. As expected, the thinnest QW sample (0.5 monolayer) results in the smallest EA of 23 meV, whereas the thickest QW sample (1.4 monolayer) results in the highest EA of 79 meV. Carrier lifetime has been calculated from TRPL measurement for varying temperatures. At 10 K, the carrier lifetime increased almost linearly from 250 to 800 ps with the InAs QW thickness. Thicker InAs QW results in a longer carrier lifetime, which has been explained by the carrier escape model. Higher temperatures resulted in a decrease in carrier lifetime, which suggests carrier escape is dominating the temporal decay behavior.

Cortisol awakening response prompts dynamic reconfiguration of brain networks in emotional and executive functioning

Emotion and cognition involve an intricate crosstalk of neural and endocrine systems that support dynamic reallocation of neural resources and optimal adaptation for upcoming challenges, an active process analogous to allostasis. As a hallmark of human endocrine activity, the cortisol awakening response (CAR) is recognized to play a critical role in proactively modulating emotional and executive functions. Yet, the underlying mechanisms of such proactive effects remain elusive. By leveraging pharmacological neuroimaging and hidden Markov modeling of brain state dynamics, we show that the CAR proactively modulates rapid spatiotemporal reconfigurations (state) of large-scale brain networks involved in emotional and executive functions. Behaviorally, suppression of CAR proactively impaired performance of emotional discrimination but not working memory (WM), while individuals with higher CAR exhibited better performance for both emotional and WM tasks. Neuronally, suppression of CAR led to a decrease in fractional occupancy and mean lifetime of task-related brain states dominant to emotional and WM processing. Further information-theoretic analyses on sequence complexity of state transitions revealed that a suppressed or lower CAR led to higher transition complexity among states primarily anchored in visual-sensory and salience networks during emotional task. Conversely, an opposite pattern of transition complexity was observed among states anchored in executive control and visuospatial networks during WM, indicating that CAR distinctly modulates neural resources allocated to emotional and WM processing. Our findings establish a causal link of CAR with brain network dynamics across emotional and executive functions, suggesting a neuroendocrine account for CAR proactive effects on human emotion and cognition.

Visualization and Estimation of 0D to 1D Nanostructure Size by Photoluminescence.

We elaborate a method for determining the 0D-1D nanostructure size by photoluminescence (PL) emission spectrum dependence on the nanostructure dimensions. As observed, the high number of diamond-like carbon nanocones shows a strongly blue-shifted PL spectrum compared to the bulk material, allowing for the calculation of their top dimensions of 2.0 nm. For the second structure model, we used a sharp atomic force microscope (AFM) tip, which showed green emission localized on its top, as determined by confocal microscopy. Using the PL spectrum, the calculation allowed us to determine the tip size of 1.5 nm, which correlated well with the SEM measurements. The time-resolved PL measurements shed light on the recombination process, providing stretched-exponent decay with a τ0 = 1 ns lifetime, indicating a gradual decrease in exciton lifetime along the height of the cone from the base to the top due to surface and radiative recombination. Therefore, the proposed method provides a simple optical procedure for determining an AFM tip or other nanocone structure sharpness without the need for sample preparation and special expensive equipment.

Observation of Excited State-Derived Photoluminescence Decay of Organic Dye to Monitor Its Photo-Induced Charge Transfer Efficiency

Understanding photo-induced charge transfer (PCT) is crucial for optimizing the performance of solar-powered devices like photovoltaic and photoelectrochemical cells, as PCT directly impacts their operation and overall power conversion efficiency. General assessment of PCT has heavily relied on transient absorption techniques to gauge electron transfer between the donor and acceptor. However, there is a pressing need to broaden the methods for comprehensively studying PCT.In this study, we propose an alternative approach utilizing transient photoluminescence to observe PCT dynamics between organic dyes and redox mediators. This approach involves adsorbing various organic dyes onto Al2O3 surfaces along with redox mediators. When excited, the dyes facilitate charge separation from each other, leading to the instantaneous oxidized form of the dye and subsequent electron transfer from the redox mediator. This process results in a decrease in the photoluminescence lifetime of the organic dye. The extent of this decreases correlates with the Gibbs free energy of charge transfer, reflecting the efficiency of electron transfer between the organic dye and the redox mediator. Our findings introduce an alternative avenue for studying PCT, offering insights that are pertinent to various fields including photovoltaics, optoelectronics, and photocatalysis. Figure 1

Coupling Time-Resolved Mass Spectrometry Techniques to Unravel Cobalt Degradation Mechanisms in Acidic Media for Oxygen and Hydrogen Electrocatalysis

Cobalt plays a significant role within sustainable energy technologies, including but not limited to hydrogen fuel cells for transportation, lithium-ion batteries for electric vehicles and portable devices, and electrolyzers for renewable hydrogen production. For devices that contain a proton exchange membrane (PEM), such as proton exchange membrane fuel cells (PEMFCs) and proton exchange membrane water electrolyzers (PEMWEs), cobalt-based materials are commonly used to perform the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER), respectively. However, the PEM in these devices induces an acidic environment (pH = 1) that cobalt is thermodynamically unstable in under ORR and HER relevant potentials. This instability results in cobalt dissolution and as a consequence, substantial decreases in device performance and lifetime. To mitigate such dissolution of cobalt-based materials in acidic environments, a holistic understanding of cobalt’s degradation mechanism is required. To gain such an understanding, we have developed an experimental platform with comparable in-situ and operando techniques, including on-line inductively coupled plasma mass spectrometry (ICP-MS) and electrochemical mass spectrometry (EC-MS), to concurrently monitor relationships between electrochemical output (current/voltage), time, cobalt dissolution, and product formation (i.e, H2 and H2O).Under HER relevant potentials in acidic media (0.1 M HClO4), it was observed that cobalt is active for HER and undergoes little to no dissolution (< 10 ppb Co2+) while evolving H2, per comparable EC-MS and ICP-MS experiments. These observations suggest that cobalt stability in acidic media strongly coincides with hydrogen evolution. Additionally, these data showcase a surprising window of stability for cobalt that is different than would have been predicted with classical chemical thermodynamics (i.e., Pourbaix diagrams). Along with cobalt being HER active, we have also uncovered its activity for ORR in acidic media (O2 saturated 0.1 M HClO4). Furthermore, the rate of cobalt dissolution was different in O2 versus N2 saturated electrolyte, where it was observed that cobalt dissolution initially occurs faster (~3x more dissolution) in the presence of O2. Altogether, this work showcases how time-resolved techniques such as ICP-MS and EC-MS can be combined to unravel material degradation mechanisms, with cobalt as a case study. This experimental platform has high potential to accelerate current understandings of material degradation, paving the way for new avenues to design and develop more robust and affordable materials and devices.

Impact of Combined Zr, Ti, and V Additions on the Microstructure, Mechanical Properties, and Thermomechanical Fatigue Behavior of Al-Cu Cast Alloys

The effects of minor additions of the transition elements Zr, Ti, and V on the microstructure, mechanical properties, and out-of-phase thermomechanical fatigue behavior of 224 Al-Cu alloys were investigated. The results revealed that the introduction of the transition elements led to a refined grain size and a finer and much denser distribution of θ″/θ′ precipitates compared to that of the base alloy, which enhanced the tensile strength but reduced the elongation at both room temperature and 300 °C. Constitutive analyses based on theoretical strength calculations indicated that precipitation strengthening was the primary mechanism contributing to the strength of both tested alloys at room temperature and 300 °C. The out-of-phase thermomechanical fatigue test results showed that the addition of transition elements caused a slight decrease in the fatigue lifetime, which was mainly attributed to the reduced ductility and higher peak tensile stress at low temperatures. During the fatigue process, the transition element-added alloy exhibited a lower coarsening ratio, indicating higher thermal stability, which mitigated the negative impact of the reduced ductility on the fatigue performance to some extent. Considering their various properties, the addition of Zr, Ti, and V is recommended to improve the overall performance of Al-Cu 224 cast alloys.

Micrometer-Resolution Fluorescence and Lifetime Mappings of CsPbBr3 Nanocrystal Films Coupled with a TiO2 Grating.

Enhancing light emission from perovskite nanocrystal (NC) films is essential in light-emitting devices, as their conventional stacks often restrict the escape of emitted light. This work addresses this challenge by employing a TiO2 grating to enhance light extraction and shape the emission of CsPbBr3 nanocrystal films. Angle-resolved photoluminescence (PL) demonstrated a 10-fold increase in emission intensity by coupling the Bloch resonances of the grating with the spontaneous emission of the perovskite NCs. Fluorescence lifetime imaging microscopy (FLIM) provided micrometer-resolution mapping of both PL intensity and lifetime across a large area, revealing a decrease in PL lifetime from 8.2 ns for NC films on glass to 6.1 ns on the TiO2 grating. Back focal plane (BFP) spectroscopy confirmed how the Bloch resonances transformed the unpolarized, spatially incoherent emission of NCs into polarized and directed light. These findings provide further insights into the interactions between dielectric nanostructures and perovskite NC films, offering possible pathways for designing better performing perovskite optoelectronic devices.

A novel ZnO-TiO2-Bi2WO6/Carboxymethyl chitosan composite with high antimicrobial activity and visible-light catalytic degradation of ethylene towards banana preservation in hot and humid environments

In order to solve the problem of significantly shortened storage time of bananas in hot and humid environment (e.g., 30 °C and 90 % relative humidity), this paper reports the preparation of ZnO-TiO2-Bi2WO6 (ZTB) ternary heterojunction antimicrobial photocatalysts composite carboxymethyl chitosan film (ZTB/CMCS). ZTB were prepared by hydrothermal method and composited with CMCS by surface deposition method to construct ZTB/CMCS edible nano-preservation film. It is noteworthy that the ZTB/CMCS composite film exhibited excellent antibacterial efficiency (>99.99 %) against E. coli and S. aureus suspensions (106 CFU/mL) after 24 h of incubation at 37 °C. Time-resolved photoluminescence (TRPL) spectroscopy showed that the incorporation of Zinc oxide nanoparticles (ZnO NPs) into the ZTB structure led to a decrease in fluorescence lifetime. Moreover, the interfacial interaction between ZnO and TiO2/Bi2WO6 inhibited the recombination of photogenerated electron-hole pairs, promoting carrier separation and improving photocatalytic activity. The combination of high antibacterial activity, photocatalytic degradation of ethylene and inhibition of gas exchange provided multiple protections for fruit preservation. Therefore, this work provides a novel, effective and safe method for prolonging the preservation of bananas in hot and humid environments.

MoS2-CZTS: a 2D-3D nanocomposite to enhance the photocatalytic performance in degradation of methylene blue dye

Cu2ZnSnS4 nanocrystals (CZTS NCs), MoS2 nanosheet (NS) and MoS2-CZTS nanocomposite (NC) have been synthesized using solvothermal route. Structural characterization of samples have been done by XRD, Raman spectroscopy, HR-TEM. Samples have optically characterized by UV-Vis absorption, photoluminescence (PL) and time co-related single photon counting (TCSPC) study. The XRD, HR-TEM and Raman spectroscopy established tetragonal kesterite phase for both CZTS NCs and MoS2-CZTS NC. Enhancement of efficiency of CZTS NCs to degrade methylene blue (MB) dye, illuminated by visible light, have been observed by loading 1 wt.% MoS2 NS and found to be ~100% in only 15 minutes. This is due to efficent transfer of charge carriers at p-CZTS and n-MoS2 heterojunction interface, confirmed by quenching of PL intensity and decrease in average lifetime of carriers.

Lifetime maximization of IoT-enabled smart grid applications using error control strategies

Recently, with the advancement of Internet of Things (IoT) technology, IoT-enabled Smart Grid (SG) applications have gained tremendous popularity. Ensuring reliable communication in IoT-based SG applications is challenging due to the harsh channel environment often encountered in the power grid. Error Control (EC) techniques have emerged as a promising solution to enhance reliability. Nevertheless, ensuring network reliability requires a substantial amount of energy consumption. In this paper, we formulate a Mixed Integer Programming (MIP) model which considers the energy dissipation of EC techniques to maximize IoT network lifetime while ensuring the desired level of IoT network reliability. We develop meta-heuristic approaches such as Artificial Bee Colony (ABC) and Particle Swarm Optimization (PSO) to address the high computation complexity of large-scale IoT networks. Performance evaluations indicate that the EC-Node strategy, where each IoT node employs the most energy-efficient EC technique, yields a minimum of 8.9% extended lifetimes compared to the EC-Net strategies, where all IoT nodes employ the same EC method for a communication. Moreover, the PSO algorithm reduces the computational time by 77% while exhibiting a 2.69% network lifetime decrease compared to the optimal solution.

Lifetime prediction of copper pillar bumps based on fatigue crack propagation

2.5D package realizes the interconnection of multiple dies through Si interposers, which can greatly improve the data transmission rate between dies. However, its multi-layer structure and high package density also place higher reliability requirements on the interconnection structure. As a key structure for interconnection, copper pillar bump (CPB) has small size, high heat generation, and thermal mismatch with silicon chips. The thermal fatigue failure of CPB has gradually become the main failure mode in 2.5D package. Due to the small size of CPB and the large proportion of intermetallic compound (IMC) layers, the lifetime prediction method of spherical solder joints is no longer suitable for CPB. Therefore, it is necessary to establish a fatigue lifetime prediction method for CPB. This paper establishes a method for obtaining the lifetime of CPB based on the basic theory of fatigue crack propagation. Using the extended finite element simulation method, the crack propagation lifetime of CPB under thermal cycling was obtained, and the influence of different IMC layer thickness on the fatigue lifetime of CPB was analyzed. The results indicated that the fatigue lifetime of cracks propagating in the IMC layer is lower than that of cracks propagating in the solder layer, and an increase in the thickness of the IMC layer leads to a significant decrease in the fatigue lifetime of CPB. The lifetime prediction method for CPB proposed in this paper can be used for reliability evaluation of 2.5D package, and has certain reference value for the study of the lifetime of CPB.

Intricate Evaporation Dynamics in Different Multidroplet Configurations.

We experimentally investigate the evaporation dynamics of an array of sessile droplets arranged in different configurations. Utilizing a customized goniometer, we capture side and top view profiles to monitor the evolution of height, spread, contact angle, and volume of the droplets. Our results reveal that the lifetime of a droplet array surpasses that of an isolated droplet, attributed to the shielding effect induced by neighboring droplets, which elevates the local vapor concentration, thereby reducing the evaporation rate. We found that lifetime increases as droplet separation distance decreases at a fixed configuration and substrate temperature. It is observed that the lifetimes increase with the number of droplets. We observe a decrease in lifetimes, following a power law trend, with increasing substrate temperature, with the shielding effect diminishing at higher substrate temperatures due to natural convective effects. We also observe a generalized behavior for the centrally placed droplet across various separation distances and substrate temperatures. This arises from different droplet configurations and substrate temperatures, which modify the local vapor concentration around the droplets without significantly impacting the contact line dynamics. Additionally, the experimental results are compared with a diffusion-based theoretical model that incorporates the evaporative cooling effect to predict the lifetime of the central droplet within the array. We observe that the theoretical model satisfactorily predicts the lifetime of the droplet at room temperature. However, for high-temperature cases, the model slightly overpredicts the evaporative lifetimes.

Enhanced Structure/Interfacial Properties of Single‐Crystal Ni‐Rich LiNi0.92Co0.04Mn0.04O2 Cathodes Synthesized Via LiCl‐NaCl Molten‐Salt Method

Arising from the increasing demand for electric vehicles (EVs), Ni‐rich LiNixCoyMnzO2 (NCM, x + y + z = 1, x ≥ 0.8) cathode with greatly increased energy density are being researched and commercialized for lithium‐ion batteries (LIBs). However, parasitic crack formation during the discharge–charge cycling process remains as a major degradation mechanism. Cracking leads to increase in the specific surface area, loss of electrical contact between the primary particles, and facilitates liquid electrolyte infiltration into the cathode active material, accelerating capacity fading and decrease in lifetime. In contrast, Ni‐rich NCM when used as a single crystal exhibits superior cycling performances due to its rigid mechanical property that resists cracking during long charge–discharge process even under harsh conditions. In this paper, we present comparative investigation between single crystal Ni‐rich LiNi0.92Co0.04Mn0.04O2 (SC) and polycrystalline Ni‐rich LiNi0.92Co0.04Mn0.04O2 (PC). The relatively improved cycling performances of SC are attributed to smaller anisotropic volume change, higher reversibility of phase transition, and resistance to crack formation. The superior properties of SC are demonstrated by in situ characterization and battery tests. Consequently, it is inferred from the results obtained that optimization of preparation conditions can be regarded as a key approach to obtain well crystallized and superior electrochemical performances.

Substantial breakdown of the hydrogen-bonding network, local density inhomogeneities and fluid-liquid structural transitions in supercritical octanol-1: A molecular dynamics investigation.

Molecular dynamics simulations have been employed to explore the hydrogen-bonding structure and dynamics in supercritical octanol-1 at a near-critical temperature and up to high densities and pressures. A substantial breakdown of the hydrogen-bonding network when going from ambient-liquid to supercritical conditions is revealed. The fraction of the non-hydrogen bonded molecules significantly increases in supercritical octanol-1, and a substantial decrease in the intermittent hydrogen-bond lifetime is observed. This behavior is also reflected on the maximum local density augmentation, which is comparable to the values obtained for non-polar and non-hydrogen bonded fluids. The existence of a structural transition from an inhomogeneous fluid phase to a soft-liquid one at densities higher than 2.0 ρc is also revealed. At higher densities, a significant change in the reorientational relaxation process is observed, reflected on the significant increase in the ratio of the Legendre reorientational times τ1R/τ2R. The latter becomes much higher than the value predicted by the Debye model of diffusive reorientation and the corresponding ratio for ambient liquid octanol-1. The non-polar tail of octanol-1 under supercritical conditions reorients more slowly in comparison with the polar tail. Interestingly, the opposite behavior is observed for the ambient liquid, further verifying the strong effect of the breakdown of the hydrogen bonding network on the properties of supercritical octanol-1. In accordance with the above-mentioned findings, the static dielectric constant of supercritical octanol-1 is very low even at high densities and pressures, comparable to the values obtained for non-polar and non-hydrogen bonded fluids.

Longitudinal associations between time perspective and life satisfaction across adulthood

Time perspective is an important predictor of well-being. How time is represented, is itself subject to developmental change. A time perspective dominated by the future is increasingly replaced by one focused on the present and past as remaining lifetime decreases. These age-related changes supposedly are associated with higher subjective well-being. Previous studies yielded heterogeneous results. However, these studies mostly investigated one dimension of time perspective and did not include younger and/or middle-aged adults. Thus, we investigated how changes in four facets of time perspective (past-orientation, concreteness of future time, obsolescence, and attitudes towards finitude) were related to changes in life and domain-specific satisfaction and if these relations were moderated by age. We used 10-year longitudinal data from an age-diverse sample comprising 459 participants (30–80 years). Concreteness was most consistently related to satisfaction. Individuals with overall higher concreteness reported higher life satisfaction and higher life satisfaction was reported on measurement occasions with higher concreteness. An age moderation was only found for satisfaction with mental fitness. Among younger but not older adults, satisfaction with mental fitness was higher on measurement occasions with higher concreteness. Our study provides a deeper understanding of the relation between time perspective and well-being across adulthood.

A developed DQ control method for shunt active power filter to improve power quality in transformers.

Power transformers are the most important component in power system. Exposing these transformers to the harmonic distortions causes additional heat losses, insulation stress, decrease in lifetime of insulation, and reduced power factor with decrease in efficiency of the system. The lifespan of distribution transformers is influenced by the fragility of power quality in power networks. Harmonic mitigation filters with robust control technique are required to reduce the harmonic effects on power transformer. Traditionally, synchronous reference frame (DQ) is employed to control the shunt active power filter (APF) for mitigation of harmonics in power transformers. DQ control of Shunt APF lacks merits of fast response, delayed operation due to phased lock loop under abnormal grid conditions leading to insufficient harmonic elimination. A developed DQ method based on detecting the positive and negative sequence components is proposed to precisely control the shunt APF for reliable operation of power transformer. This detection technique improves the response time, mitigate the harmonics effecting the operation of transformer and overall power factor. The proposed control system is evaluated under different abnormal operating scenarios and compared with traditional DQ method. The results and analysis confirm the efficacy of the developed DQ method in improving the power transformer performance.

Study of Concentration Quenching and Energy Transfer Mechanism in Ce Doped Y2O3 Nanomaterials.

We study concentration quenching and energy transfer mechanisms of yttrium oxide (Y2O3) nanomaterials doped with different concentrations (0-5mol%) of cerium (Ce). Photoluminescence (PL) spectra recorded under an excitation wavelength of 350nm show a broad emission band at ∼ 406nm and a feeble emission band at ∼ 463nm in the undoped Y2O3 sample. The doping of Ce in Y2O3 induced multiple PL peaks within the blue-green region of the spectrum in all the doped samples with the peak at ∼ 466nm being notably the prominent one. This prominent emission band exhibits a decrease in intensity with increasing Ce concentration due to concentration quenching. Analysis of Time-resolved photoluminescence (TRPL) spectra reveal that the average emission lifetime of Ce-doped Y2O3 is shorter than that of the undoped Y2O3 sample. The concentration quenching effect and the decrease of average emission lifetime of the dominant emission band are explained on the basis of energy transfer from the host Y2O3 to the Ce3+ ion centres. The critical quenching concentration of Ce3+ ion in Y2O3:Ce phosphor was identified to be 1mol% and the critical transfer distance was estimated to be 23.74 Å. Analysis reveal that the concentration quenching mechanism involves nearest-neighbour interaction.

Comparative analysis of microstructure, electrical and optical performance in sidewall etching process for GaN-based green micro-LED

Micro-LEDs show the size-dependent external quantum efficiency (EQE) reduction problem, mainly owing to increased non-radiative recombination loss at the sidewall for smaller chip size. In this work, the evolution of microstructure, surface potential and optical performance of the green micro-LED sidewall was investigated comparatively after inductively coupled plasma (ICP) and tetramethylammonium hydroxide (TMAH) etching through transmission electron microscopy (TEM), Kelvin probe force microscope (KPFM), cathodoluminescence (CL) and time-resolved photoluminescence (TRPL). As confirmed by TEM and geometric phase analysis (GPA), ICP etching causes sidewalls to form atomically rough semi-polar surfaces and increases 25% compressive strain at the sidewall compared to the inside. TMAH solution introduces new sidewall defects due to excessive etching of three atomic layers of InGaN. Holes accumulate at the surface because of build-in electric field as showed by KPFM. The sidewall defects lead to a decrease in carrier lifetime resulting in uneven luminescence of micro-LED mesa. TMAH treatment removes the damaged layer and reduces the non-radiative recombination rate. ICP causes damage to the nanoscale structure, however the influence of sidewall defects on the carrier behavior is in the micron range due to unavoidable surface dangling bonds and surface lattice relaxation. A non-radiative recombination mechanism is proposed based on strain relaxation.

Plasmon-enhanced fluorescence for biophotonics and bio-analytical applications.

Fluorescence spectroscopy serves as an ultrasensitive sophisticated tool where background noises which serve as a major impediment to the detection of the desired signals can be safely avoided for detections down to the single-molecule levels. One such way of bypassing background noise is plasmon-enhanced fluorescence (PEF), where the interactions of fluorophores at the surface of metals or plasmonic nanoparticles are probed. The underlying condition is a significant spectral overlap between the localized surface plasmon resonance (LSPR) of the nanoparticle and the absorption or emission spectra of the fluorophore. The rationale being the coupling of the excited state of the fluorophore with the localized surface plasmon leads to an augmented emission, owing to local field enhancement. It is manifested in enhanced quantum yields concurrent with a decrease in fluorescence lifetimes, owing to an increase in radiative rate constants. This improvement in detection provided by PEF allows a significant scope of expansion in the domain of weakly emitting fluorophores which otherwise would have remained unperceivable. The concept of coupling of weak emitters with plasmons can bypass the problems of photobleaching, opening up avenues of imaging with significantly higher sensitivity and improved resolution. Furthermore, amplification of the emission signal by the coupling of free electrons of the metal nanoparticles with the electrons of the fluorophore provides ample opportunities for achieving lower detection limits that are involved in biological imaging and molecular sensing. One avenue that has attracted significant attraction in the last few years is the fast, label-free detection of bio-analytes under physiological conditions using plasmonic nanoparticles for point-of-care analysis. This review focusses on the applications of plasmonic nanomaterials in the field of biosensing, imaging with a brief introduction on the different aspects of LSPR and fabrication techniques.