Ultra-fast determination of quantum efficiency of a solar cell
First Claim
1. A light source for use in testing of solar cells and other optical spectroscopy applications, comprising:
- an array of light sources emitting light corresponding with a differing portion of a test spectrum; and
a power supply comprising modulated power supplies coupled to each of the light sources, wherein the modulated power supplies operate at unique operating frequencies to drive sets of one or more of the light sources at the differing portions of the test spectrum;
wherein the unique operating frequencies are not multiples of each other and wherein the modulated power supplies are configured to selectively vary power levels delivered to select an intensity of the light emitted from each of the LEDS, whereby the test spectrum can be matched to a particular spectrum.
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Accused Products
Abstract
An apparatus for measuring quantum efficiency (QE) of solar cells. The apparatus includes a light source including an array of light emitting diodes (LEDs) that each emit light corresponding to a differing portion of a test spectrum and each LED is driven by a sinusoidal power supply that operates at a unique frequency. The light source includes an optical coupling focusing the LED light into a test beam targeted on a solar cell, and a signal conditioner converts analog current signals generated by the solar cell into digital voltage signals. A QE measurement module determines a QE value corresponding to each of the LEDs based on the digital voltage signals using a Fast Fourier Transform module that processes the digital voltage signals to generate values for each operating frequency. The QE measurement module determines the QE values by applying a conversion factor to these values. Since all the LEDs can be power-modulated simultaneously and the corresponding cell responses to each of the LEDS can be analyzed simultaneously, the QE spectrum measurement time is greatly shortened as compared to conventional methods.
24 Citations
26 Claims
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1. A light source for use in testing of solar cells and other optical spectroscopy applications, comprising:
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an array of light sources emitting light corresponding with a differing portion of a test spectrum; and a power supply comprising modulated power supplies coupled to each of the light sources, wherein the modulated power supplies operate at unique operating frequencies to drive sets of one or more of the light sources at the differing portions of the test spectrum;
wherein the unique operating frequencies are not multiples of each other and wherein the modulated power supplies are configured to selectively vary power levels delivered to select an intensity of the light emitted from each of the LEDS, whereby the test spectrum can be matched to a particular spectrum. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for measuring full spectrum quantum efficiency (QE) of a solar cell, comprising
a light source emitting light corresponding with differing portions of a test spectrum and an optical coupling focusing the emitted light into a test beam; -
a signal conditioning assembly receiving analog current signals responsive to the test beam striking the solar cell and converting the analog current signals into digital voltage signals; and a QE determination system in communication with the signal conditioning assembly comprising a processor running a QE measurement module determining a QE value corresponding to each of the differing portions of the test spectrum based on the digital voltage signals, wherein all wavelengths of light are applied simultaneously to the solar cell, wherein the analog current signal responses of the solar cell from various wavelengths are collected simultaneously. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A method of performing optical spectroscopy of a test subject, comprising:
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providing a light source powered by a modulated power supply; positioning the test subject proximate an output of the light source; operating the light source to emit light corresponding with a plurality of wavelengths in a test spectrum, wherein the emitted light is focused in a test beam upon a surface of the test subject; and determining a plurality of test result values responsive to the test beam striking the surface of the test subject wherein the determining of the test result values comprises converting analog current signals generated by the test subject into digital voltage signals and determining a quantum efficiency (QE) value corresponding to each of the wavelengths in the test spectrum based on the digital voltage signals. - View Dependent Claims (15, 16, 17, 18)
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19. An optical spectroscopy system configured to perform ultra-fast determinations or measurements of characteristics of a test object, the optical spectroscopy system comprising
a light source configured to emit light corresponding with differing portions of a test spectrum and an optical coupling configured to focus emitted light into a test beam; -
a signal conditioning assembly configured to receive analog current signals responsive to the test beam striking the test object and converting analog current signals into digital voltage signals; and a quantum efficiency (QE) determination system in communication with the signal conditioning assembly, the QE determination system comprising a processor configured to run a QE measurement module, wherein the QE measurement module is configured to determine a QE value corresponding to each of the differing portions of the test spectrum based on the digital voltage signals, wherein all wavelengths of light are applied simultaneously to the test object, wherein the analog current signal responses of the test object from various wavelengths are collected simultaneously. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
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Specification