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Search Publications by: Behrang Hamadani (Fed)

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Displaying 26 - 50 of 127

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

August 26, 2021
Author(s)
Brianna Conrad, Behrang Hamadani
There is a fundamental understanding in photovoltaics 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

Solar Cell Performance Measurements Under Artificial Lighting Sources

January 5, 2021
Author(s)
Behrang Hamadani
In recent years, there has been a growing interest in measurements of photovoltaic solar cells under ambient artificial lighting such as light emitting diode (LED) or fluorescent light sources. Certain classes of solar cells are considered very good

Understanding Photovoltaic Energy Losses under Indoor Lighting Conditions

July 28, 2020
Author(s)
Behrang H. Hamadani
The external luminescence quantum yield as a function of the solar cell current density when exposed to low indoor light was estimated based on absolute electroluminescence measurements and a self-consistent use of the electro-optical reciprocity

3D printed optical concentrators for LED arrays

July 19, 2020
Author(s)
Behrang H. Hamadani, Jonathan E. Seppala, Clarence J. Zarobila
Additive manufacturing methods based on photopolymerization offer a great potential for fabrication of high quality, highly transparent optical components. One appropriate use of these technologies is related to fabrication of parts that can be used in

Reconciling LED and Monochromator-based Measurements of Spectral Responsivity

August 1, 2019
Author(s)
John F. Roller, Behrang H. Hamadani
The irradiance spectral responsivity is an important measurement characteristic for a reference solar cell and has served as a primary reference cell calibration method for a growing number of national labs in recent years. This paper discusses the process

Nonlinear Response of Silicon Solar Cells

January 1, 2019
Author(s)
Behrang H. Hamadani, Andrew M. Shore, Howard W. Yoon, Mark Campanelli
We used an LED-array-based combinatorial flux addition method to explore the wavelength and the intensity-dependence of the spectral responsivity in silicon solar cells. Many types of silicon cells, whether mono- or multi-crystalline type, exhibit notable

Modulated Photocurrent Measurements in Double Junction Solar Cells

November 4, 2018
Author(s)
Nicolas Marquez Peraca, Behrang Hamadani
Frequency dependent external quantum efficiency (EQE) measurements were performed on double junction solar cells by a custom-designed system consisting of an array of various monochromatic LEDs. Some LEDs were pulsed as a function of frequency while others

Frequency response of the external quantum efficiency in multijunction solar cells

June 29, 2017
Author(s)
Nicolas Marquez Peraca, D T. Bilir, Behrang Hamadani
The frequency dependence of the external quantum efficiency (EQE) of high-quality multijunction solar cells was examined by the modulated photocurrent spectroscopy method via an optical setup comprised of a light-pipe-coupled compact LED array. The optical