Brianna Conrad

Large Area Via-Enabled Back Contact Thermophotovoltaic Cells for a High Power Density System

Brianna Conrad, Walker R. Chan, Veronika Stelmakh

Commercialization of thermophotovoltaic (TPV) cells and applications requires not only good efficiencies, but high power output, the two of which may be independent. Back contacted cell architectures have the potential to improve the power output of a TPV system through reduced series …

Beam-based commissioning of a novel X -band transverse deflection structure with variable polarization

P. González Caminal, Florian Christie, Richard D’Arcy, S. Jaster-Merz et autres

Longitudinal electron-beam diagnostics play a critical role in the operation and control of x-ray free-electron lasers, which rely on parameters such as the current profile, the longitudinal phase space, or the slice emittance of the particle distribution. On the one hand, the …

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Below the Urbach Edge: Solar Cell Loss Analysis Based on Full External Quantum Efficiency Spectra

Jakub Holovský, Katarína Ridzoňová, Amalraj Peter Amalathas, Brianna Conrad et autres

High Resolution Image Download MS PowerPoint Slide We suggest a new solar cell loss analysis using the external quantum efficiency (EQE) measured with sufficiently high sensitivity to also account for defects. Unlike common radiative-limit methods, where the impact of deep defects is …

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Identifying and investigating spatial features in InGaAs solar cells by hyperspectral luminescence imaging

Brianna Conrad, Behrang H. Hamadani

Hyperspectral luminescence imaging adds high-resolution spectral data to electroluminescence and photoluminescence images of photovoltaic materials and devices. This enables absolute calibration across a range of spectra, and subsequently enhances the information that can be gained from such measurements. We present a temperature-dependent …

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Visualizing localized, radiative defects in GaAs solar cells

Behrang H. Hamadani, Margaret A. Stevens, Brianna Conrad, Matthew P. Lumb et autres

We have used a calibrated, wide-field hyperspectral imaging instrument to obtain absolute spectrally and spatially resolved photoluminescence images in high growth-rate, rear-junction GaAs solar cells from 300 to 77 K. At the site of some localized defects scattered throughout the active layer, …

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10.1063/5.0097572.1

Brianna Conrad, Behrang H. Hamadani

Hyperspectral electroluminescence and photoluminescence imaging of photovoltaic materials and devices produces three-dimensional spatially and spectrally resolved luminescence data, which can be calibrated to an absolute scale, enabling the extraction of high resolution maps of quantities, such as the local voltage (quasi-Fermi-level splitting). …

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Local voltage mapping of solar cells in the presence of localized radiative defects

Brianna Conrad, Behrang H. Hamadani

Hyperspectral electroluminescence and photoluminescence imaging of photovoltaic materials and devices produces three-dimensional spatially and spectrally resolved luminescence data, which can be calibrated to an absolute scale, enabling the extraction of high resolution maps of quantities such as the local voltage (quasi-Fermi-level splitting). …

us (code pays fourni par la source)

10.1063/5.0097572.2

Brianna Conrad, Behrang H. Hamadani

Hyperspectral electroluminescence and photoluminescence imaging of photovoltaic materials and devices produces three-dimensional spatially and spectrally resolved luminescence data, which can be calibrated to an absolute scale, enabling the extraction of high resolution maps of quantities, such as the local voltage (quasi-Fermi-level splitting). …

us (code pays fourni par la source)

Hyperspectral Luminescence Imaging Analysis of Solar Cells with Localized Radiative Defects

Brianna Conrad, Behrang H. Hamadani

Absolute hyperspectral electroluminescence and photoluminescence imaging is used to investigate properties of localized radiative defects in GaAs cells, including local voltage, or quasi-Fermi-level splitting, EQE and absorptivity. Previous methods to determine these quantities rely on assumptions that may not be valid in …

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Hyperspectral Imaging of Localized, Optically-Active Defects in GaAs Solar Cells

Behrang H. Hamadani, Margaret A. Stevens, Brianna Conrad, Matthew P. Lumb et autres

A novel hyperspectral imaging instrument with dual electroluminescence and photoluminescence capability was used to image and analyze localized radiative defects in rear-junction GaAs solar cells grown at 1$\boldsymbol{\mu} \mathbf{m}/\boldsymbol{\min}$. The absolute photon emission rates were measured over a wide spectral range encompassing …

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Heterosubstrate Illumination Effects in III–V Solar Cells

Brianna Conrad, Behrang H. Hamadani

Reference cell based current vs voltage (IV) measurements assume that the effect of an illumination spectrum on a solar cell's performance can be fully captured by the multiplication of the spectrum with the device's spectral response and subsequent integration. This is based …

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Investigating Sub-bandgap Spectral Effects in GaInP-on-Ge Solar Cells

Brianna Conrad, Behrang H. Hamadani

There is a fundamental understanding in photo-voltaics that sub-bandgap light will not be absorbed in the solar cell and therefore will not affect the power generation. We have shown a novel phenomenon in which sub-bandgap illumination is required for good electrical performance …

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