However, said quantum yields were quite different for the two systems. The lower-power EAP-00 system showed very high apparent quantum yields (AQY) of 41-71% over the whole range of the studied light intensities (considering 6 transferred electrons per turnover, Table ). This is lower than what was previously reported for this reaction using methanol as a solvent, the difference likely attributable to the fact that isopropanol oxidation is slower than methanol and it also liberates less electrons from follow-up reactions. However, the quantum yield for the higher-powered EAP-01 system showed a significantly lower apparent quantum yield of 14-22%. Consequently, even though the light intensity in this system is 16 times as high, the reaction rate is only enhanced by a factor of 3.4. This is likely the results of the higher light intensity leading to lower efficiency due to kinetic limitations. An analysis of the dependence of the nitrobenzene reduction rate on the light intensity (albeit with methanol as solvent) showed a linear dependency up to light intensities corresponding to an irradiance of about 25-40 mW cm -2 . In the case of the WLE, the majority of the light is emitted in a cone with an angle of 130° from the LED. This corresponds to a surface of approximately 0.91 cm² on the outside of the 1 cm diameter WLE (Figure ) that is exposed to the reaction medium and thus an estimated irradiance of 104.6 mW cm -2 on this area based on the calculated average emission of 95.2 mW of the EAP-01 system. This irradiance is virtually invariant of the number of WLE employed as due to the high optical density of the reaction medium, overlapping effects of individual emitters are negligible. However, with a higher number of emitters, the total area and volume exposed to this maximum irradiance increases, which is akin to a more uniform light distribution. It should also be noted that the locally absorbed photon flux around a point source such as these WLE is significantly lower for a given irradiance than for an area source typical for external irradiation due to the additional axial attenuation (conical rather than cylindrical beam propagation). In the case of the EAP-00 system, the irradiance is estimated at only 6.3 mW cm -2 due to the much lower emission of each emitter. This explains the different observed quantum yields of the two systems as the lower power system is still operated in the photon-limited regime with maximum quantum yield. However, the EAP-01 system's irradiance exceeds the reported linear limit by a factor of 3-4, therefore leading to a lowered efficiency. Nonetheless, there are no additional inefficiencies when further increasing the light intensity through a higher number of emitters as the maximum irradiance over each emitter is constant.