A schematic of a typical setup (taken from the ASTM E1021-15standard) is shown below. We start with a broadband light source, meaning one emitting a wide range of wavelengths. In order to not be as heavil. Once you've gotten responsivity through the test described above, the EQE is really easy to calculate. We've already seen the equation that allows us to do this: Where h is Planck's constant, c is the speed of light, q is the charge o. It turns out that, using the method described above for measuring responsivity, we also get enough information to calculate the total current out of the device. However, a much more practical method. If we rearrange the efficiency equation from earlier, we see that we can calculate the efficiency as soon as we know the maximum power point, and the incident power: One thing to be careful of is that the power has to be t. Because there is a great deal of work both commercial and academic in the field of photovoltaics, there is also a great need for standardization of the methods and means of comparing one device to another. NREL has done an impr.