Alternative and fully experimental procedure for characterizing down-shifters placed on photovoltaic devices

Evolution of the external quantum efficiency of Si-based PV minimodules with encapsulated down-shifters and aged under UV radiation

“…Moreover, the obtained results of the sample faced up initially are slightly higher than for the sample faced down. This result is attributed to the fact that the glass substrate absorption is dependent on the wavelengths of the incident photons, as we have described elsewhere [25]. However, the slope observed under UV degradation is higher for the DS facing up directly to the UV light than for the sample with the DS facing down.…”

“…The EQEs for mc-Si and CIGS modules with record efficiencies are added to fig. 3 to show that DS layers on high efficient c-Si and mc-Si solar modules can be detrimental for enhancing the efficiency of such devices, as we have explained elsewhere [25]. However, the high UV transparency of such devices could accelerate the passivation degradation of the solar cell, as it has been described in recent works [43,44].…”

“…Moreover, in this work, the ageing of the devices is controlled and accelerated in a climatic chamber for a more precise description of the impact of UV radiation on the stability of Eu3+ complex embedded in PMMA DS layer in increasing conversion efficiency. This work is an extension of a recent work showing an alternative and fully experimental procedure for characterizing DS placed on PV devices [25].…”

“…The solvent was evaporated at room temperature. Samples with 20% relative weight concentration of the active species with respect to the PMMA were obtained [25].…”

“…Moreover, as we have described previously, analyzing the effect of the integration of a DS in a spectral range where the EQE of the bare PV device is not negligible can be very difficult because the EQE of the PV device integrating the DS is the result of the two competing efficiencies (the DS and the bare PV cell) and the transmittance of the DS layer [25]. This makes difficult to analyze the results of the only scientific paper detected in the literature where a DS is encapsulated to a PV cell using a procedure close to the standard industrial process because the EQE of the PV cell encapsulated with clear ethylene vinyl acetate (EVA) is above 19% in the 300 -400 nm spectral range [23].…”