Angle of incidence effects on external quantum efficiency in multicrystalline silicon photovoltaics

The accurate prediction of photovoltaic power output under a wide range of conditions observed in the field is of significant interest to the effective insertion of solar power into the electric grid. Spectrally resolved external quantum efficiency (EQE) is used to compute changes in the short-circuit current density as a function of the incidence angle, thus providing a cell-level performance metric that can be integrated into an irradiance-to-power model, allowing an alternative to empirically derived parameters. Multicrystalline silicon cells have been examined both in their as-received condition and after the addition of an EVA/top glass laminate structure. The use of a physical mask in the EQE measurement has allowed the isolation of the expected cosine law behavior from the contribution of optical effects associated with reflection and scattering that are unique to cell/module materials and architecture.