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Accelerated Discovery of Two-Dimensional Optoelectronic Octahedral Oxyhalides via High-Throughput <i>Ab Initio</i> Calculations and Machine Learning
摘要： Traditional trial-and-error methods are obstacles for large-scale searching of new optoelectronic materials. Here, we introduce a method combining high-throughput ab initio calculations and machine-learning approaches to predict two-dimensional octahedral oxyhalides with improved optoelectronic properties. We develop an effective machine-learning model based on an expansive data set generated from density functional calculations including the geometric and electronic properties of 300 two-dimensional octahedral oxyhalides. Our model accelerates the screening of potential optoelectronic materials of 5000 two-dimensional octahedral oxyhalides. The distorted stacked octahedral factors proposed in our model play essential roles in the machine-learning prediction. Several potential two-dimensional optoelectronic octahedral oxyhalides with moderate band gaps, high electron mobilities, and ultrahigh absorbance coefficients are successfully hypothesized.
关键词： band gaps,optoelectronic materials,two-dimensional octahedral oxyhalides,absorbance coefficients,electron mobilities,high-throughput ab initio calculations,machine learning
更新于2025-09-19 17:13:59
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[IEEE 2019 41st Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC) - Berlin, Germany (2019.7.23-2019.7.27)] 2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Hyperspectral imaging for thermal effect monitoring in in vivo liver during laser ablation
摘要： Thermal ablation is a minimally invasive technique used to induce a controlled necrosis of malignant cells by increasing the temperature in localized areas. This procedure needs an accurate and real-time monitoring of thermal effects to evaluate and control treatment outcome. In this work, a hyperspectral imaging (HSI) technique is proposed as a new and non-invasive method to monitor ablative therapy. HSI provides images of the target object in several spectral bands, hence the reflectance/absorbance spectrum for each pixel. This paper presents a preliminary and original HSI-based analysis of the thermal state in the in vivo porcine liver undergoing laser ablation. In order to compare the spectral response between treated and untreated areas of the organ, proper Regions of Interest (ROIs) were chosen on the hyperspectral images; for each ROI, the absorbance variation for the selected wavelengths (i.e., 630, 760, and 960nm, for deoxyhemoglobin, methemoglobin, and water respectively) was assessed. Results obtained during and after laser ablation show that the absorbance of the methemoglobin peaks increases up to 40% in the burned region with respect to the non-ablated one. Conversely, the relative change of deoxyhemoglobin and water peaks is less marked. Based on these results, absorbance threshold values were retrieved and used to visualize the ablation zone on the images. This preliminary analysis suggests that a combination of the absorbance information is essential to achieve a more accurate identification of the ablation region. The results encourage further studies on the correlation between thermal effects and the spectral response of biological tissues undergoing thermal ablation, for final clinical use.
关键词： laser ablation,absorbance spectrum,in vivo porcine liver,hyperspectral imaging,thermal ablation
更新于2025-09-16 10:30:52
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Tailoring a Molecule’s Optical Absorbance Using Surface Plasmonics
摘要： Understanding the interaction of light with molecules physisorbed on substrates is a fundamental problem in photonics, with applications in biosensing, photovoltaics, photocatalysis, plasmonics, and nanotechnology. However, the design of novel functional materials in silico is severely hampered by the lack of robust and computationally efficient methods for describing both molecular absorbance and screening on substrates. Here we employ our hybrid G0[W0 + ?W]-BSE implementation, which incorporates the substrate via its screening ?W at both the quasiparticle G0W0 level and when solving the Bethe-Salpeter equation (BSE). We show this method can be used to both efficiently and accurately describe the absorption spectra of physisorbed molecules on metal substrates and thereby tailor the molecule’s absorbance by altering the surface plasmon’s energy. Specifically, we investigate how the optical absorption spectra of three prototypical π-conjugated molecules: benzene (C6H6), terrylene (C30H16) and fullerene (C60), depends on the Wigner-Seitz radius rs of the metallic substrate. To gain further understanding of the light–molecule/substrate interaction, we also study the bright exciton’s electron and hole densities and their interactions with infrared active vibrational modes. Our results show that (1) benzene’s bright E1 2u exciton at 7.0 eV, whose energy is insensitive to changes in rs, could be relevant for photocatalytic dehydrogenation and polymerization reactions, (2) terrylene’s bright B3u exciton at 2.3 eV hybridizes with the surface plasmon, allowing the tailoring of the excitonic energy and optical activation of a surface plasmon-like exciton, and (3) fullerene’s π ? π? bright and dark excitons at 6.4 and 6.8 eV hybridize with the surface plasmon, resulting in the tailoring of their excitonic energy and the activation of both a surface plasmon-like exciton and a dark quadrupolar mode via symmetry breaking by the substrate. This work demonstrates how a proper description of interfacial light–molecular/substrate interactions enables the prediction, design, and optimization of technologically relevant phenomena in silico.
关键词： Plasmonics,Optical Absorbance,π-conjugated molecules,Fullerene,Excitons,Hybrid Materials,Benzene,Surface Plasmonics,Magnetic,Infrared active vibrational modes,Wigner-Seitz radius,Optical,Terrylene
更新于2025-09-16 10:30:52
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Plasmonic Nanoassemblies: Tentacles Beat Satellites for Boosting Broadband NIR Plasmon Coupling Providing a Novel Candidate for SERS and Photothermal Therapy
摘要： Optical theranostic applications demand near-infrared (NIR) localized surface plasmon resonance (LSPR) and maximized electric field at nano-surfaces and nanojunctions, aiding diagnosis via Raman or optoacoustic imaging, and photothermal-based therapies. To this end, multiple permutations and combinations of plasmonic nanostructures and molecular “glues” or linkers are employed to obtain nanoassemblies, such as nano-branches and core–satellite morphologies. An advanced nanoassembly morphology comprising multiple linear tentacles anchored onto a spherical core is reported here. Importantly, this core-multi-tentacle-nanoassembly (CMT) benefits from numerous plasmonic interactions between multiple 5 nm gold nanoparticles (NPs) forming each tentacle as well as tentacle to core (15 nm) coupling. This results in an intense LSPR across the “biological optical window” of 650?1100 nm. It is shown that the combined interactions are responsible for the broadband LSPR and the intense electric field, otherwise not achievable with core–satellite morphologies. Further the sub 80 nm CMTs boosted NIR-surface-enhanced Raman scattering (SERS), with detection of SERS labels at 47 × 10-9 m, as well as lower toxicity to noncancerous cell lines (human fibroblast Wi38) than observed for cancerous cell lines (human breast cancer MCF7), presents itself as an attractive candidate for use as biomedical theranostics agents.
关键词： branched polymers,core–satellites,surface-enhanced Raman scattering (SERS),plasmonic nanoassemblies,broadband NIR absorbance,cell toxicity
更新于2025-09-16 10:30:52
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Graphene’s photonics and optoelectronics properties – A Review
摘要： Due to its remarkable electrical and optical properties, graphene continues to receive more and more attention from researchers around the world. An excellent advantage of graphene is the possibility of controlling its charge density, and consequently, the management of its conductivity and dielectric constant, among other parameters. It is noteworthy that the control of these properties enables the obtaining of new optical/electronic devices, which would not exist, based on conventional materials. However, to work in this area of science, it is necessary a thorough knowledge regarding the electrical/optical properties of graphene. In this review paper, we show these graphene properties very well detailed.
关键词： Absorbance (78.20.-e),Conductivity (78.20.-e),Substrate (78.40.Fy),Reflectance (78.20.-e),Surface plasmons polaritons (73.20.Mf),Transmittance (78.20.-e),Dispersion relation (11.55.Fv),Dielecric constant (31.15.es)
更新于2025-09-12 10:27:22
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Magnetic-induced graphene quantum dots for imaging-guided photothermal therapy in the second near-infrared window
摘要： Graphene quantum dots (GQDs) are considered emerging nanomaterials for photothermal therapy (PTT) of cancer due to their good biocompatibility and rapid excretion. However, the optical absorbance of GQDs in shorter wavelengths (<1000 nm) limits their overall therapeutic efficacies as photothermal agent in the second near infrared window (1000-1700 nm, NIR-II). Herein, we report a type of GQDs with strong absorption (1070 nm) in NIR-II region that was synthesized via a one-step solvothermal treatment using phenol as single precursor by tuning the decomposition of hydrogen peroxide under a high magnetic field with an intensity of 9T. The obtained 9T-GQDs demonstrate uniform size distribution (3.6 nm), and tunable fluorescence (quantum yield, 16.67 %) and high photothermal conversion efficacy (33.45%). In vitro and in vivo results indicate that 9T-GQDs could efficiently ablate tumor cells and inhibit the tumor growth under NIR-II irradiation. Moreover, the 9T-GQDs exhibited enhanced NIR imaging of tumor in living mice, suggesting the great probability of using 9T-GQDs for in vivo NIR imaging-guided PTT in the NIR-II window.
关键词： magnetic field,NIR-II absorbance,photothermal conversion,cancer therapy,graphene quantum dot
更新于2025-09-12 10:27:22
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Triple mode coupling effect and dynamic tuning based on the zipper-type graphene terahertz metamaterial
摘要： We construct a laminated metamaterial structure of zipper-type monolayer graphene with silica which equipped with a distinctively dual plasmon induced transparency (PIT) phenomenon. The graphene pattern in this structure crafty connects with the electrode so that we can dynamically control the PIT response (via regulating the bias voltage that applied between the electrode and the substrate to control the graphene Fermi energy). In which, the range of voltage-regulate is calculated theoretically that proved to be a feasible measure for PIT response-tune. Then, the tuning discipline for this structure is summarized from the calculated result of coupled mode theory (CMT) deduced theoretical model and the simulation result. It is found that the structure possesses a great tuning performance within the tuning range we studied; also, such the structure ameliorates the monolayer graphene absorbance from 2.3% to about 50% within a broad dynamic frequency tuning range, the absorption peak frequency modulation depth is up to 45.46%. Besides, the group refractive index is discussed for reflecting the system capability of slow light, and the maximum of the coefficient can catch up to 595. Even if the impact of dielectric light- absorbance to slow light is taken into account, the slow light index at the transparent window is still as high as 200.
关键词： Absorbance,Plasmon induced transparency,Dynamic tuning,Slow light device,Graphene metamaterial
更新于2025-09-12 10:27:22
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Monolayer HfTeSe4: A promising two-dimensional photovoltaic material for solar cells with high efficiency
摘要： Currently, atomically thin materials with high photovoltaic performance are urgently needed for applications in solar cells. Herein, by using first-principles calculations, we propose an excellent two-dimensional photovoltaic material, monolayer HfTeSe4, which can be exfoliated feasibly from its layered bulk. It behaves the semiconductor character with a moderate direct gap of 1.48 eV and exhibits remarkable absorbance coefficient of ~105 cm-1 in visible-light region. Meanwhile, monolayer HfTeSe4 shows ultrahigh photocurrent and a long carrier recombination life-time. And strain engineering can further modulate the recombination time of carriers. Moreover, the heterostructure between HfTeSe4 and Bi2WO6 is proposed as potential solar cells with the solar conversion efficiency up to ~20.8%. These extraordinary properties combined with its experimental feasibility makes monolayer HfTeSe4 particularly promising for photovoltaic device applications.
关键词： absorbance coefficient,solar conversion efficiency,carrier recombination,photovoltaic,first-principles calculations,photocurrent
更新于2025-09-12 10:27:22
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Self‐Assembled Polyamidoamine Dendrimer on Poly (methyl meth‐ acrylate) for Plasmonic Fiber Optic Sensors
摘要： We report a novel one-step polyamidoamine (PAMAM) dendrimer based polymethyl methacrylate (PMMA) surface functionalization strategy for the development of polymeric optical (POF) based plasmonic sensors utilizing gold nanoparticles (AuNP). Simple contact angle measurements over PMMA sheets reveal the ability of the dendrimers to strongly bind to PMMA surface without additional acid/alkali pretreatment, unlike the conventional hexamethylene diamine (HMDA) based surface modification. Subsequently, U-bent POF probes with high evanescent wave absorbance sensitivity were exploited for relative quantification of the surface amine groups using fluorescein isothiocyanate (FITC) binding and efficient chemisorption of gold nanoparticles (AuNP) in order to identify the optimum conditions viz. dendrimer concentration, incubation time and dendrimer generation. While FITC binding showed a proportional increase in amine functional density with PAMAM concentration and time, interestingly the AuNP (40 nm) binding studies revealed the formation of loose PAMAM multilayers and their desorption. PAMAM (G4) concentration as low as 5 mM and incubation time of 24 h provide faster binding rate with densely packed AuNP and the RI sensitivity of ~ 15 (A546 nm/RIU). This simpler and inexpensive strategy could also be exploited for the development of functional PMMA substrates for various applications including nanotechnology, bio-imaging, drug delivery and analytical separations.
关键词： gold nanoparticles (AuNP),dendrimers,plasmonic sensors,polymethyl methacrylate (PMMA),polymeric optical fibers (POF),evanescent wave absorbance
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Quantum Sensing of Absorbance and the Beer-Lambert Law
摘要： Optical quantum sensing strategies that utilise features of quantum states of light have implications for precision measurement in areas as wide ranging as such as gravitational wave sensing and biological imaging. Optical absorption estimation is the task of estimating the transmission parameter η which is defined by the ratio of input, (cid:1835)(cid:3036)(cid:3041), to output, (cid:1835)(cid:3042)(cid:3048)(cid:3047), intensity of light from a sample of interest ((cid:1835)(cid:3042)(cid:3048)(cid:3047) = (cid:2015)(cid:1835)(cid:3036)(cid:3041)). The optimal quantum strategy provides a quantum advantage (per incident photon) of 1/(1-η) over the best classical strategy. This technique has been demonstrated experimentally in single parameter estimation and imaging scenarios. Here, we expand on recent theoretical and experimental results and investigate the quantum advantage available for absorbance estimation, where the parameter of interest, α, is the loss per unit length parameter used in the Beer-Lambert law: (cid:1835)(cid:3042)(cid:3048)(cid:3047) = exp(?α (cid:1838))(cid:1835)(cid:3036)(cid:3041), where (cid:1838) is the length of the sample. We further show that the tunability of (cid:1838) allows for maximisation of the Fisher information. Furthermore, we show that the optimal length, (cid:1838)(cid:3042)(cid:3043)(cid:3047), that provides the largest Fisher information is a function of the photon number statistics of the input optical state, and as such is different for optimal quantum and classical schemes. When both strategies are operating at (cid:1838)(cid:3042)(cid:3043)(cid:3047), the quantum advantage is limited to a fixed value of 1.2 for all α, contrary to absorption estimation where the quantum advantage can be arbitrarily large. This demonstrates that an improvement in the precision of the sensor can be performed by classical means, drastically reducing the advantage offered by quantum strategies. We find the impact of (cid:1838)(cid:3042)(cid:3043)(cid:3047) is analogous to previous work looking at multipass strategies for phase estimation. Using the setup depicted in Figure 1, we experimentally show that for single photon Fock states, optimising over (cid:1838) does indeed yield higher precision estimates of absorbance. This work has implications for a range of experiments employing the Beer-Lambert law, and can be expanded to include other experimental parameters such as loss, dark counts, and noisy laser sources.
关键词： Absorbance,Quantum Advantage,Fisher Information,Beer-Lambert Law,Quantum Sensing
更新于2025-09-11 14:15:04