Advanced module optics of textured perovskite silicon tandem solar cells

Perovskite silicon tandem solar cells can overcome the efficiency limit of single junction silicon solar cells. Optical modeling plays a crucial role for the device optimization but it becomes complex if optically thin and thick layers as well as interface textures, such as random pyramids, are involved. Within this work, the OPTOS simulation formalism is applied in order to compare perovskite silicon tandem solar cells with planar and textured front side. Modeling the configuration with planar front side and textured rear exhibits a matched photocurrent density of 18.2 mA/cm2. For the system with textured front and planar rear side the reduced reflectance leads to a photocurrent density of 19.6 mA/cm2 although parasitic absorption in the Spiro-OMeTAD and ITO layers increases. Taking into account the full module stack in the OPTOS simulation shows an increased front side reflectance and parasitic absorption in the EVA. The difference between the resulting photocurrent densities (17.8 mA/cm2 and 18.9 mA/cm2) demonstrates the optical superiority of the investigated system with textured front side not only at cell level but also in the full module stack.