Optical management of spacer layer of high-performance four-terminal perovskite/silicon tandem solar cells

Abstract Perovskite/silicon tandem solar cell (TSC) is a promising strategy to receive high power conversion efficiency (PCE), exceeding the Shockley-Queisser (S-Q) limit of single junction SC. However, the reflected light still dominates the loss of photocurrent, happened at the surface and interface of two sub cells. Here, a suitable spacer layer is accepted to manage the light harvesting in the four-terminal (4T) perovskite/silicon TSC. The influence of microstructure, refractive index and thickness of spacer layer on the photocurrent has been systematically studied by the photoelectric simulation. And then the designed spacer layer is a double-side textured structure with a refractive index (RI) of 1.4 in 4 μm thickness, receiving the best light-harvesting to being the largest photocurrent. Furthermore, the relationship of light-absorption between perovskite and silicon SCs is investigated as a function of bandgap and thickness of perovskite, yielding the optimal photocurrent of 21.65 mA/cm2 and 19.71 mA/cm2 for top and bottom cells, respectively. Finally, four types of industrialized silicon SCs are integrated into the TSCs to study the photoelectric performance in detail, predicting the theoretical limitation PCE of 33.52%. Therefore, this simulated study provides a theoretical guide for the optical design of high-efficiency 4T TSCs.