Polychromatic determination of spectral response of PV devices
2014-05-13T11:26:00Z (GMT) by
This thesis introduces a novel spectral response (SR) measurement technique using polychromatic filters (filters with very broad spectral transmittances) to determine SR of large area PV devices. Conventionally, SR of a photovoltaic (PV) device is determined by illuminating the device under test (DUT) with a series of monochromatic beams at different wavelengths as described in the international standard IEC 60904-8, or beams of limited spectral content using narrow band pass filters or monochromator. One significant problem associated with the application of the narrow band pass filters for a large-area SR measurement is that low light intensity produced on the measurement plane particularly in certain wavelength ranges: the ultraviolet and infrared. This can produce weak signal responses from a tested PV device. In addition, the imperfection of the filter s mounting position can shift the peak wavelength of the filter s transmittance at angle of incidence greater than 10. This can cause stray light on the measurement plane. The proposed SR measurement method is called as the polychromatic SR fitting method or, in short, it is known as the polychromatic method . The advantage of this method is that higher beam intensity can be produced on the measurement plane as a result of large spectral transmittance of the polychromatic filters. This can improve the signal strength of a tested PV device. This new SR measurement method works by comparing the variations in the currents which are measured at different spectra to the currents which are calculated at the same spectral conditions using the SR model. Validations of this method for a large- and small-area SR determinations show that it is potentially feasible as a new technique for determining SR of a PV device with deviations within ±2% across the wavelength bands.