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

Abstract

For the first time to our knowledge, a study about the increase in external quantum efficiency (EQE) by down-shifters (DS) encapsulated by industrial procedures on photovoltaic (PV) modules is presented. EQE improves substantially in the UV range not only because of the optical path optimization for photons reaching the solar cell, but also it is attributed to the substantial reduction of DS photons scattered out of the solar cell when the outermost surface of the DS layer is embedded in ethyl-vinyl-acetate. Consequently, a proper encapsulation of DS layers is required for the optimal characterization of EQE. Moreover, the encapsulation of the DS layer substantially reduces the degradation of its luminescent properties due to UV radiation. However, the reduction of the EQE under UV radiation for the encapsulated DS layer is still high and should be substantially reduced for the integration of down-shifting properties in the lamination process of PV modules.