- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Tuning Bandgap of Mixed-Halide Perovskite for Improved Photovoltaic Performance Under Monochromatic-Light Illumination
摘要： Organic–inorganic halide perovskites have emerged as promising materials for optoelectronic devices. This paper focuses on a new application field for perovskite materials as monochromatic-light conversion devices. First the optical properties of organic–inorganic perovskite semiconductors with bandgaps varying from near-infrared to visible at room temperature are presented. Two types of hybrid organic–inorganic mixed-halide perovskites, (FAPbI3)x(MAPbBr3)1-x and FA0.85MA0.15Pb(IxBr1-x)3, are adopted for bandgap tuning, an approximate linear variation of bandgaps with the x value is obtained. The relationship between thin film composition and device performance are investigated. Based on the results of the above bandgap tuning, two kinds of devices with bandgap near the wavelength of 683 nm are characterized under monochromatic-light illumination. A conversion efficiency of up to 40% under 60 mW cm?2 monochromatic-light illumination is achieved. The results confirm that the perovskite films exhibit sharp optical absorption edge, enabling highly efficient monochromatic-light conversion device.
关键词： monochromatic-light,hybrid mixed-halide perovskites,bandgap tuning,photovoltaic performance
更新于2025-11-25 10:30:42
-
Comparison between broadband and monochromatic photopic negative response in full-field electroretinogram in controls and subjects with primary open-angle glaucoma
摘要： Purpose A prospective, cross-sectional, case–control study was conducted to investigate the role of broadband and monochromatic photopic negative response (PhNR) of the full-field flash electroretinogram (ERG) in the evaluation of ganglion cell damage in primary open-angle glaucoma (POAG) subjects. Methods Subjects with POAG and age-matched normal subjects were recruited from the outpatient department of a tertiary eye care center in South India. A total of 25 patients with POAG and 50 age-matched normal subjects were recruited. ERG was recorded using broadband (3.5 cd.s/m2 white stimulus on 10 cd/m2 white background) and monochromatic (3.5 cd.s/m2 red stimulus on 10 cd/m2 blue background and 1 cd.s/m2 blue stimulus on 10 cd/m2 yellow background) stimuli. Results The reduction in PhNR amplitude in POAG compared to normal individuals was higher in red-on-blue PhNR [26.37 μV; p < 0.001, confidence interval (CI) 19.34 to 33.4] as compared to broadband stimuli (16.41 μV; p < 0.001, CI 8.68 to 24.13), and blue on yellow (21.96 μV; p < 0.001, CI 10.12 to 33.8). Red-on-blue PhNR amplitudes correlated better with mean deviation (MD; r = -0.66, p < 0.05), pattern standard deviation (PSD; r = -0.4, p = 0.04), visual field index (VFI; r = -0.58, p < 0.05), and retinal nerve fiber layer thickness (r = -0.67, p < 0.05) in comparison with broadband and monochromatic blue-on-yellow PhNR. Receiver operating characteristic curve revealed largest area under the curve (0.89) in red-on-blue PhNR compared to broadband (0.76) and blue on yellow (0.74). The sensitivity and specificity was also higher in red-on-blue PhNR (72% and 80%, respectively) as compared to the other stimuli (sensitivity and specificity of broadband 0.68 and 0.7, blue on yellow 0.64 and 0.7, respectively). Conclusion Correlation of PhNR with Humphrey visual field parameters and retinal nerve fiber layer thickness showed that red-on-blue PhNR can be a useful additional tool for clinical assessment of retinal ganglion cell dysfunction in glaucoma patients. Red-on-blue PhNR was more sensitive as compared to white-on-white and blue-on-yellow PhNR in identifying ganglion cell dysfunction and correlates well with other structural and functional tests for glaucoma such as MD, PSD, VFI, and RNFL thickness.
关键词： Primary open-angle glaucoma,Photopic negative response,Broadband ERG,Full-field electroretinogram,Monochromatic ERG
更新于2025-09-23 15:23:52
-
AIP Conference Proceedings [Author(s) THE 3RD INTERNATIONAL SEMINAR ON CHEMISTRY: Green Chemistry and its Role for Sustainability - Surabaya, Indonesia (18–19 July 2018)] - Green synthesis of silver nanoparticles using photo-induced reduction method
摘要： Silver Nanoparticles (AgNPs) has been successfully synthetized in this study using photoinduced reduction method with monochromatic light. In this method we use sodium citrate as capping agent without additional reducing agent. Silver nanoparticles characterized using Ultraviolet-Visible Spectroscopy (UV-Vis) and X-ray Diffraction (XRD). The synthetized AgNPs show that wavelength of light can affect the properties of AgNPs based on absorption spectra of UV-Vis. XRD measurement showed the characteristic peak of silver at 2θ of 38.060, 44.140, 64.470, and 77.400.
关键词： Photochemistry,Reduction,Sodium Citrate,AgNPs,Monochromatic light
更新于2025-09-23 15:23:52
-
[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - The Influence of Coherent Monochromatic and Non-monochromatic Electromagnetic Radiation on the Human Brain Rhythms
摘要： This work is aimed at studying the effect of non-monochromatic electromagnetic radiation in the visible range on the rhythms of the human brain and a comparison of the results obtained with that known in the literature about the influence of coherent monochromatic radiation on the brain rhythms. At the present time, research results indicate that effect of monochromatic and non-monochromatic electromagnetic radiation on biological objects is identical. It can be also stated that comprehensive investigations concerning the influence of electromagnetic radiation of the visible range on human brain rhythms have not been carried out yet. We carried out experiments on electromagnetic radiation effects of the visible range on brain rhythms. The hand skin of visually impaired peoples was irradiated by visual light of different wavelength and the effects were registered by using complex KSD. Our experiments have shown that the rhythms of the brain vary depending on the wavelength of the electromagnetic radiation. The experiments have also shown that initially low activity of alpha rhythm level in the visually impaired people strongly depends on the wavelength of electromagnetic radiation acting on the hand skin, despite the fact that the people’s attention was constantly focused on their sensations. At the same time other researchers have found an increase in alpha rhythms in response to laser stimuli, which may be associated with cognitive processes: focusing on tasks and sensations, although vision, hearing and somatosensory processes suppress the alpha rhythms. The results obtained have not only theoretical, but also the great practical interest, since it may assist in an effective treatment of various diseases.
关键词： brain rhythms,coherent monochromatic radiation,non-monochromatic radiation
更新于2025-09-23 15:21:01
-
Time-resolved imaging of atoms and molecules in laser-produced uranium plasmas
摘要： Gas-phase oxidation of uranium (U), plume chemistry, and the corresponding impact on optical emission features of the U plasma are investigated. Plasmas were produced via nanosecond laser ablation of a natural U target in a chamber where U oxidation was controlled by varying the oxygen partial pressure in an argon cover gas. Monochromatic imaging of U atoms and monoxide (UO) molecules was performed using narrow bandpass optical filters. Results reveal the spatio-temporal evolution of atomic and molecular species in the plasma. U oxides are found to be formed further from the target (in comparison to U atoms), where lower temperatures favor molecular recombination. Segregation between the distribution of U atoms and UO species is observed at later times of plasma evolution, and is more apparent at lower oxygen partial pressures. At higher oxygen partial pressures, significant variation in plume morphology is noticed for UO species, which can be attributed to the higher oxide (UxOy) formation further from the target. The monochromatic images of U atoms and UO molecules and corresponding spectral features at various oxygen partial pressures presented here provide unique insight into gas-phase, high-temperature U oxidation and chemistry, with implications for a wide range of nuclear applications, from stand-off detection of radioisotopes to forensics and safeguards.
关键词： optical emission spectroscopy,plasma,uranium,laser ablation,monochromatic imaging
更新于2025-09-16 10:30:52
-
[IEEE 2019 IEEE 4th Optoelectronics Global Conference (OGC) - Shenzhen, China (2019.9.3-2019.9.6)] 2019 IEEE 4th Optoelectronics Global Conference (OGC) - The Comparative Study of Using Si and Te Doping Tunnel Junction of Vertical Hetero-structure Laser Photovoltaic Cell
摘要： Heavy doping of epitaxial tunnel junction layers is of interest in vertical hetero-structure laser photovoltaic cell the performance characteristic of AlGaAs/GaAs junctions with silicon(Si) and tellurium (Te) doped were presented, respectively. Compared to Si doping, the tunnel junction diode doped with Te doping revealed lower tunneling resistance and better performance. A comparative study using both Si and Te doping in the AlGaAs/GaAs tunnel junction of six junctions monochromatic laser photovoltaic cells also showed a higher photoelectric efficiency for Te doping. Therefore, the tunnel junction with Te doping can be considered to improve the performance of monochromatic laser cells.
关键词： si-doped,tunnel junction,te-doped,monochromatic laser cell,efficiency
更新于2025-09-16 10:30:52
-
Physics, Pharmacology and Physiology for Anaesthetists (Key Concepts for the FRCA) || Laser principles
摘要： Lasers are used in many types of surgery and the examinations will test both your understanding of their underlying principles and aspects related to laser safety. LASER is an acronym that stands for Light Amplification by Stimulated Emission of Radiation. The definition of the word laser also gives a very succinct description of its mode of action. A lasing medium describes the type of laser, for example a ‘CO2’ laser contains CO2 as the lasing medium. The medium is pulsed with energy from an external source, typically an intense light or electrical discharge. The application of external energy raises the electrons in the lasing medium to a higher orbit or energy state around their host atom. When the pulsed external energy is off, the excited electrons return to a lower energy orbit and, in doing so, release photons (light). The wavelength of this light is dependent upon the nature of the lasing medium and the energy difference between the high energy and low energy orbits. Photons travel in random directions although some will travel parallel to the walls of the container that holds the lasing medium. This container has mirrors at both ends that reflect the photons back and forth through the medium. As each photon hits an electron in the excited state it stimulates it to release its own photon and, in doing so, to return to a lower energy orbit. The phenomenon of this stimulated release of photons is that they share the same wavelength and phase as the photon causing the release. The mirror at one end of the container is partially mirrored in that it reflects a proportion of the photons that hit it but also allows a proportion of them out of the container as laser light. Three important properties of laser light produced by this process are that it is monochromatic, collimated and coherent.
关键词： coherent,Laser,monochromatic,Light Amplification by Stimulated Emission of Radiation,collimated
更新于2025-09-12 10:27:22
-
[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) - Experimental Observation of Coexisting Differently Polarized Cavity Solitons in a Monochromatically Driven Passive Kerr Resonator
摘要： Temporal cavity solitons (CSs) are pulses of light that can recirculate in coherently-driven, dispersive, Kerr resonators without changes in their shape or energy. They underpin applications such as fiber resonator all-optical buffers [1] and coherent microresonator frequency combs [2]. Because they are associated with a unique attractor of the underlying dynamical system, all CSs coexisting in a resonator are expected to be identical. However, studies have shown [2, 3], that if two different cavity modes are simultaneously driven, nonidentical CSs can coexist. In [2], two orthogonal polarization modes were driven with a bichromatic field and coexistence of differently polarized nonidentical CSs was observed. According to [4], under certain conditions the same can be achieved using a monochromatic field, a prospect yet to be experimentally confirmed. In this contribution, we report on the experimental observation of coexistence between two differently polarized nonidentical vector CSs (VCSs) in a monochromatically driven passive Kerr resonator. We use a 85-m-long fiber-ring resonator made out of standard single-mode fiber closed onto itself with a 95/5 coupler. The resonator supports two orthogonal principal polarization modes and is driven with synchronized flat-top pulses carved from a narrow linewidth continuous-wave laser, polarized such that both modes are excited. By changing the birefringence of our resonator with an intracavity polarization controller, the two modes are partly overlapped. The detuning of our driving laser is locked within the overlap region and nonidentical VCSs excited by mechanically perturbing the resonator. We monitor the intracavity dynamics using a real-time oscilloscope and an optical spectrum analyzer. Polarization controllers and polarizing beam-splitters are used to separately monitor the two modes of the cavity. Figures 1(a)–(c) show the roundtrip-by-roundtrip evolutions of the total and polarization resolved intracavity intensities. Two VCSs are trapped to opposite edges of our 4.5 ns driving pulses [Fig. 1(a)]; polarization resolved measurements reveal they have different polarizations [Figs. 1(b) and (c)]. Figures 1(d) and (e) show optical spectra measured along the two polarization axes. Since the VCSs are associated with different detunings, they exhibit different spectral widths, which also implies different temporal durations and peak powers [c.f. Fig. 1(f)]. In conclusion, we have made the first experimental observation of coexisting differently polarized nonidentical VCSs in a monochromatically driven passive Kerr resonator. Our findings could be relevant for multiplexed microresonator frequency comb systems.
关键词： vector cavity solitons,Kerr resonator,Temporal cavity solitons,monochromatic field,polarization
更新于2025-09-11 14:15:04
-
A Monochromatic Soft X-ray Generation from Femtosecond Laser-produced Plasma with Aluminum
摘要： A tabletop ultrafast soft x-ray has been generated from the laser-produce plasma with a femtosecond pulsed Ti:Sapphire laser. The estimated total ?ux of Al Kα is of 2.2 × 109 photons/sec in 4π radian and the parameters related to the optical performance were obtained. The tungsten/silicon multilayer, ?at quartz and bent thallium acid phthalate (TLAP) crystal were used for monochromatization of soft x-ray to re?ne the aluminum Kα radiation and compared the respective value of E/ΔE. To estimate the size of the x-ray source beam generated by a fs laser, the approximation using the FWHM obtained from the x-ray beam scan near the focal point was discussed, and the size of the diameter was about 9.76 μm.
关键词： Monochromatic,Aluminum,Soft x-ray,XRD,Femtosecond laser
更新于2025-09-11 14:15:04
-
Accuracy of Quantification of Iodine and Hounsfield Unit Values on Virtual Monochromatic Imaging Using Dual-Energy Computed Tomography
摘要： The aim of the study was to compare the accuracy of quantification of iodine and Hounsfield unit (HU) values on virtual monochromatic imaging (VMI) using dual-layer computed tomography (DLCT) and fast kilovolt-switching computed tomography (FKSCT). Materials and Methods: This study was performed in 2 phantoms (large and small) using 16 rods representing different materials (iodine, calcium, blood, and adipose tissue) with different dimensions and concentrations. The absolute percentage errors (absolute ratio of measurement error to true iodine concentration) for iodine concentration and HU value on VMI at 50, 70, and 100 keV were compared between DLCT and FKSCT. The Mann–Whitney U test was used to assess statistical significance. Results: Overall, the absolute percentage errors for iodine concentration and HU value on VMI were smaller for DLCT than for FKSCT. Conclusions: Overall, the accuracy of iodine and HU values was higher for DLCT than for FKSCT.
关键词： virtual monochromatic imaging,dual-energy CT,fast kilovoltage-switching CT,iodine concentration,dual-layer CT
更新于2025-09-09 09:28:46