In this work, we propose an alternative and fully experimental procedure based only on external quantum efficiency (EQE) measurements for characterizing the efficiency and transmittance of downshifters placed on photovoltaic (PV) devices. The experimental setup requires two PV devices as references, one of them showing a zero EQE in the downshifting spectral range. Therefore, the results obtained are independent of the quantum efficiency of the device, easing the analysis and comparison between experimental results. Also, this method avoids complex theoretical modeling proposed in other works. Those theoretical models are usually based on approximations and/or that require some input parameters difficult to determine without a wide range of experimental equipment in the lab.
