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A detailed comparison of measured and simulated optical properties of a short-period GaAs/Al <sub/><i>x</i> </sub> Ga <sub/> 1a?? <i>x</i> </sub> As distributed Bragg reflector
摘要: A 6-period GaAs/Al0.9Ga0.1As distributed Bragg re?ector (DBR) has been grown and its optical properties have been both measured and simulated. Incremental improvements were made to the simulation, allowing it to account for internal consistency error, incorrect layer thicknesses, and absorption due to substrate doping to improve simulation accuracy. A compositional depth pro?le using secondary-ion mass spectrometry (SIMS) has been taken and shows that the Al fraction averages 88.0% ± 0.3%. It is found that the amplitude of the transmission is signi?cantly affected by absorption in the n-doped GaAs substrate, even though the energy of the transmitted light is well below the GaAs band gap. The wavelength of the features in the transmission spectrum are mostly affected by DBR layer thicknesses. On the other hand, the transmission spectrum is found to be relatively tolerant to changes to Al fraction.
关键词: optical simulation,AlGaAs,distributed Bragg re?ector,SIMS,cross section,telecoms,vertical cavity
更新于2025-09-23 15:21:01
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FDTD Optical Simulation for Organic Solar Cells Incorporated with Antireflection Nanostructures
摘要: To improve the performance of organic photovoltaics, we investigate an integrated device design in which the hybrid antireflection structure, composed of a surface moth-eye nanotexture and a multilayer interference film, is applied with a high-refractive-index glass substrate. The moth eye texture with a relatively long period, which is near the bandgap wavelength of organic semiconductors, is used to enhance light absorption. We perform the optical finite-difference time-domain simulation for the integrated device and find the optimal layer configuration of the multilayer interference film to maximize the photocurrent generation. In addition, we compare the absorption spectrum of the integrated device and that of the device with only moth eye coating, and show that the integrated structure is beneficial to realize a high level of absorption relatively uniformly as function of wavelength.
关键词: Optimization,FDTD,Organic solar cell,Optical simulation
更新于2025-09-23 15:21:01
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FDTD simulation studies on improvement of light absorption in organic solar cells by dielectric nanoparticles
摘要: In this paper, we present a systematic design and analysis of organic solar cell (OSC) by embedding dielectric nanoparticles layer at anode. Using numerical simulations, we show that there is improvement in the light absorption in the active layer of the device using nanoparticles. The nanoparticles will act as scattering medium for the incident light and hence trap the light inside the device. For the light scattered at different angles, the optical path length in the active medium is increased and this leads to more absorption of light in the active layer and thereby increase in the efficiency. The scattering efficiency and hence the absorption of solar radiation for generation of current depends on the particle size, inter-particle separation and the refractive index contrast between the particles and the embedding medium. Mie theory has been used to calculate the scattering efficiency of nanoparticles. The effect on light absorption and current density of OSC due to nanoparticles has been carried out using finite difference time domain analysis. It is shown that the proposed OSC structure increases the light absorption in the active layer of the device by 40% and short circuit current density by 34%.
关键词: Organic solar cell,Dielectric nanoparticles,Light absorption,Scattering efficiency,Optical simulation
更新于2025-09-23 15:19:57
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Structure, thermal stability and optical simulation of ZrB2 based spectrally selective solar absorber coatings
摘要: In the present work, a solar selective coating of ZrB2/Al2O3 was deposited onto stainless steel (SS) substrates using a magnetron sputtering system. The coating exhibited an good selective absorbing properties with an absorptance of 0.92 and an emittance of 0.11. To investigate the thermal stability of the coating, the samples were annealed at 500 °C and 600 °C for 100 h, respectively. Experimental results indicated that the coating was thermally stable at 500 °C. The structure and optical properties of the coating is also characterized using ultra-high resolution scanning electron microscope, UV–vis–NIR spectrophotometer, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS). The re?ectance spectra of the SS/ZrB2/Al2O3 coating was successfully simulated by CODE software.
关键词: Solar absorber coating,Optical simulation,Structure,Thermal stability
更新于2025-09-19 17:15:36
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Laser multi-focus precision cutting of thick sapphire by spherical aberration rectification
摘要: Laser multi-focus separation technology is an effective way to cut thick, transparent and hard materials. In this paper, factors affecting the quality of multi-focus cutting sapphire were investigated. Optical simulations analysis was performed based on experimental results to analyze multi-focal laser beam propagation from air into sapphire. The results show that the focus interval is linearly dependent on refractive index. Spherical aberration due to refractive-index mismatch disperses the laser foci, leading to a reduction in laser power density which has a significant influence on the cutting quality. The aberration is strongly dependent on the refractivity of the material and the effective numerical aperture (NA). By redesigning the distribution of multiple foci to correct spherical aberration, sapphire with a thickness of 2 mm was cut successfully at a scanning speed of 4 mm/s. The roughness of the cutting section was ~2.5 μm , without obvious observed micro-cracks.
关键词: Optical simulation,Spherical aberration,Multi-focus,Sapphire
更新于2025-09-19 17:13:59
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Monolithic Perovskite/Si Tandem Solar Cells: Pathways to Over 30% Efficiency
摘要: The article commences with a review focusing on three critical aspects of the perovskite/Si tandem technology: the evolution of efficiencies to date, comparisons of Si subcell choices, and the interconnection design strategies. Building on this review, a clear route is provided for minimizing optical losses aided by optical simulations of a recently reported high-efficiency perovskite/Si tandem system, optimizations which result in tandem current densities of ≈20 mAcm?2 with front-side texture. The primary focus is on electrical modeling on the Si-subcell, in order to understand the efficiency potential of this cell under filtered light in a tandem configuration. The possibility of increasing the Si subcell efficiency by 1% absolute is offered through joint improvements to the bulk lifetime, which exceeds 4 ms, and improves surface passivation quality to saturation current densities below 10 fA cm?2. Polycrystalline-Si/SiOx passivating contacts are proposed as a promising alternative to partial-area rear contacts, with the potential for further simplifying cell fabrication and improving device performance. A combination of optical modeling of the complete tandem structure alongside electrical modeling of the Si-subcell, both with state-of-the-art modeling tools, provides the first complete picture of the practical efficiency potential of perovskite/Si tandems.
关键词: electrical simulation,perovskite/Si tandem,monolithic,optical simulation,efficiency
更新于2025-09-12 10:27:22
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Luminescent properties of CaSc2O4:Ce3+ green phosphor for white LED and its optical simulation
摘要: Green-emissive Ce3t-doped CaSc2O4 phosphors were synthesized by solid-state method. The water washing process of the as-prepared samples was several times conducted because of severe hydration of unreacted CaO and CaF2 flux residual. The washed CaSc2O4:Ce3t phosphors showed a single phase with a crystallite size of 1–3 μm, and its photoluminescence intensity was 10% improved compared with the as-prepared. It shows the broad 450 nm excitation peak and the green emission peak at 520 nm with a half width of 105 nm. Its temperature dependence showed the similar thermal stability with a commercial silicate phosphor. The optical simulation and the real fabrication of white LEDs with a combination of our green phosphor and one of possible orange-red phosphors demonstrated that the white LED with Sr3SiO5:Eu2t orange phosphor gives the best luminous efficacy and the appropriate color rendering index of 70 under the daylight color temperature of 6400 K.
关键词: CaSc2O4:Ce3t,White-light-emitting diode,Optical simulation,Photoluminescence,Green emission
更新于2025-09-12 10:27:22
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Optical Simulation of the Influence of Spheres with Local Deviations on the Radius Value
摘要: The wavefront re?ected by a real sphere was supposed to in?uence signi?cantly the value of the volume determination. Therefore, optical simulations were performed to investigate the wavefront aberration and the results of simulated and inputted topographies are compared. To evaluate the valid boundary of the raytracing software a synthetic sphere with one local deviation from roundness was simulated. The software was validated with a precision of 0.01 nm for a standard sphere of 50 nm form deviation. In succession the contribution of the wavefront re?ection in the uncertainty budget could be reduced for various spheres.
关键词: optical simulation,measurement units,measurement uncertainty,uncertainty,interferometry
更新于2025-09-10 09:29:36