A method of quantum efficiency (QE) photovoltaic measurement is provided that includes coupling measurement electronics to a p-n junction of a Cell Under Test (CUT) that are capable of measuring a pulsed DC photocurrent. The measurement electronics output a response by the CUT to turning on and turning off the pulsed DC photocurrent that are digitized and analyzed for the magnitude that is representative of a conversion efficiency of the CUT to a wavelength of the DC photocurrent, where a measured decay time represents the p-n junction or the minority carrier lifetime. The CUT is exposed to the pulsed DC photocurrent, where signatures of the response to turning off and on to the pulsed DC photocurrent overlap, where a combined amplitude of the response is proportional to an efficiency of a production of photocarriers, where a value of a spectral response at a wavelength is determined.