Impact of Irradiation-Induced Filter Heating on Calibration of NIR-Longpass-Filtered Reference Solar Cells

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Reference solar cells play a crucial role in determining the performance of photovoltaic (PV) devices. In the performance calibration chain of mainstream single-junction PV technologies, common reference cell types include Si, KG-filtered Si, and GaAs cells. For emerging multijunction (MJ) PV technologies, such as CdTe&#x002F;Si and perovskite&#x002F;Si, Si reference cells with colored glass near-infrared-longpass (LP) filters like Schott RG-715 and 850 glass have been proposed. They offer a better spectral response that matches the bottom junctions of the emerging MJs, which could lead to lower uncertainties in performance measurements. However, this article reveals a prominent decrease in short-circuit current (<italic>I</italic>SC) during National Renewable Energy Laboratory&#x0027;s primary calibration over the course of minutes when using this type of LP-filtered reference cell, which could result in unacceptable measurement errors. Unlike quartz or KG filter glasses, LP colored glass filters demonstrate temperature-sensitive cut-on wavelength. When incident irradiance reaches these LP-filtered reference cells, the increased temperature due to light absorption causes a shift of the cut-on to longer wavelength. As a result, the device <italic>I</italic>SC exhibits a continuous decrease (approximately a 2.5&#x0025; drop with RG850 LP filter in a 5-min duration) even when the device temperature is controlled at 25&#x2009;&#x00B0;C. To address the temperature gradient issue between colored glass LP filter and the reference cell, we propose the direct integration of thin-film LP semiconductor layer on reference cells. This type of LP-filter-integrated cell has shown minimal temperature-related <italic>I</italic>SC variation and can serve as a more reliable reference cell source for accurate performance measurements.

Original languageAmerican English
Pages (from-to)1-7
Number of pages7
JournalIEEE Journal of Photovoltaics
StatePublished - 2023

Bibliographical note

Publisher Copyright:

NREL Publication Number

  • NREL/JA-5900-86514


  • Calibration
  • Glass
  • III-V
  • Junctions
  • longpass filter
  • measurement uncertainty
  • multijunction
  • Photovoltaic cells
  • reference solar cells
  • Si
  • Silicon
  • solar irradiance
  • temperature coefficients
  • Temperature measurement
  • Temperature sensors


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