Optimization of nanostructured high efficiency perovskite/c-Si tandem solar cells via numerical simulation (Conference Presentation)

We present optical simulations for a tandem solar cell consisting of a nanostructured thin-film perovskite top cell and a silicon heterojunction (SHJ) wafer bottom cell. The absorption and related current density are calculated using the rigorous simulations in the form of the finite element method for the nanostructured perovskite cell and a semi-empirical method for the SHJ cell. In order to reach the optimal value for the perovskite layer thickness we employ Newton’s method using derivatives obtained directly from the rigorous simulation. Using this we obtain an optimal layer thickness using typically one iteration step and eliminate the need for a parameter scan. We compare the results for different sinusoidal nanotextures applied to different layers in the multilayer thin-film perovskite top cell. The nanotextures lead to a gain in absorption and power conversion efficiency in comparison to an optimized planar reference. We also present experimental results towards a realisation of the proposed structure. These results give valuable insight for the emerging field of high efficiency perovskite/SHJ tandem solar cells.