5.1 It is the intent of these test methods to provide a recognized procedure for calibrating, characterizing, and reporting the calibration data for non-primary photovoltaic reference cells that are used during photovoltaic device performance measurements.
5.2 The electrical output of photovoltaic devices is dependent on the spectral content of the source illumination and its intensity. To make accurate measurements of the performance of photovoltaic devices under a variety of light sources, it is necessary to account for the error in the short-circuit current that occurs if the relative spectral response of the reference cell is not identical to the spectral response of the device under test. A similar error occurs if the spectral irradiance distribution of the test light source is not identical to the desired reference spectral irradiance distribution. These errors are quantified with the spectral mismatch parameter M (Test Method E973).
5.2.1 Test Method E973 requires four quantities for spectral mismatch calculations:
5.2.1.1 The quantum efficiency of the reference cell to be calibrated (see 7.1.1),
5.2.1.2 The quantum efficiency of the calibration source device (required as part of its calibration),
Note 1: See 10.10 of Test Method E1021 for the identity that converts spectral responsivity to quantum efficiency.
5.2.1.3 The spectral irradiance of the light source (measured with the spectral irradiance measurement equipment), and,
5.2.1.4 The reference spectral irradiance distribution to which the calibration source device was calibrated (see G173).
5.2.2 Temperature Corrections—Test Method E973 provides means for temperature corrections to short-circuit current using the partial derivative of quantum efficiency with respect to temperature.
5.3 A non-primary reference cell is calibrated in accordance with these test methods is with respect to the same reference spectral irradiance distribution as that of the calibration source device. Primary reference cells may be calibrated by use of Test Method E1125.
Note 2: No ASTM standards for calibration of primary reference cells to the extraterrestrial spectral irradiance distribution presently exist.
5.4 A non-primary reference cell should be rec......