Towards Perovskite Silicon Tandem Solar Cells with Optimized Optical Properties

Perovskite silicon tandem solar cells can overcome the efficiency limit of single junction solar cells. For an optimized optical performance, we propose a 2-terminal device featuring a front-side anti-reflection structure, optimized layer thicknesses, a meso-porous scaffold for the perovskite solar cell and a rear-side light-trapping structure for the silicon solar cell. To maintain the functionality of the underlying layers, we have developed a low-temperature process to realize a meso-porous TiO 2 scaffold via ultra-violet (UV) curing. With perovskite solar cell efficiencies >15%, we achieve results comparable to our conventional high-temperature (> 500°C) route. For the optical optimization of the complex tandem device with elements of different feature sizes, we apply a matrix-based formalism and show how layer thickness optimization and the rear-side light trapping can significantly improve the current of the tandem device.