Infrared photocurrent management in monolithic perovskite/silicon heterojunction tandem solar cells by using a nanocrystalline silicon oxide interlayer

We performed optical simulations using hydrogenated nanocrystalline silicon oxide (nc-SiO_x:H) as n-doped interlayer in monolithic perovskite/c-Si heterojunction tandem solar cells. Depending on the adjustable value of its refractive index (2.0 - 2.7) and thickness, nc-SiO_x:H allows to optically manage the infrared light absorption in the c-Si bottom cell minimizing reflection losses. We give guidelines for nc-SiO_x:H optimization in tandem devices in combination with a systematic investigation of the effect of the surface morphology (flat or textured) on the photocurrent density. For full-flat and rear textured devices, we found matched photocurrents higher than 19 and 20 mA/cm², respectively, using a 90 nm nc-SiO_x:H interlayer with a refractive index of 2.7.