Hybrid solar cells based on n-Si/poly(3,4-ethylenedioxythiophene):poly(styrene- sulfonate) (PEDOT:PSS) heterojunction promise to be a low cost photovoltaic technology by using simple device structure and easy fabrication process. However, due to the low conductivity of PEDOT:PSS, a metal grid deposited by vacuum evaporation method is still required to enhance the charge collection efficiency, which complicates the device fabrication process. Here, a solution-processed graphene oxide (GO)-welded silver nanowires (AgNWs) transparent conductive electrode (TCE) was employed to replace the vacuum deposited metal grid. A unique "sandwich" structure was developed by embedding an AgNW network between PEDOT:PSS and GO with a figure-of-merit of 8.6×10(-3) Ω(-1), which was even higher than that of sputtered indium tin oxide electrode (6.6×10(-3) Ω(-1)). A champion power conversion efficiency of 13.3% was achieved, because of the decreased series resistance of the TCEs as well as the enhanced built-in potential (Vbi) in the hybrid solar cells. The TCEs were obtained by facile low-temperature solution process method, which was compatible with cost-effective mass production technology.

The perovskite/silicon tandem solar cell (PK/c‐Si TSC) is a reasonable choice that can break through the efficiency limitations of silicon cells. Here, the p‐i‐n perovskite solar cell is conformally grown by the evaporation–solution combination technique on fully‐textured silicon heterojunction cells to realize two‐terminal PK/c‐Si TSCs. Due to the adverse effect of the residual PbI2 at the bottom of the perovskite bulk on device performance, a thermal‐evaporated CsBr thin layer is introduced between the perovskite layer and the hole transport layer to construct a gradient perovskite absorber for optimized energy level alignment, so as to improve the open‐circuit voltage and fill factor of the device. Finally, the PK/c‐Si tandem cell achieves an efficiency of 27.48% and is stable in nitrogen over 10 000 h.

Perovskite/silicon tandem solar cells (TSCs), especially two-terminal, with a record efficiency of 28% already realized, present great potential as low-cost and efficient substitutes for dominant silicon photovoltaics. Achieving efficiencies exceeding 30% is quite realistic, as indicated by extensive optical simulations. Super light management in monolithic perovskite/silicon TSCs is one of the prerequisites to make this a reality. In this Review, various forms of optical losses, such as reflection loss, parasitic absorption, and current mismatch, are analyzed systematically to provide a better understanding of the performance of perovskite/silicon TSCs. Particularly, a simple refractive index matching rule derived from the Fresnel equation is proposed as a basis for material selection and device design. Meanwhile, an overview of the current strategies and challenges in monolithic perovskite/silicon TSCs is provided, comprising bandgap engineering of perovskites and light trapping methods, aiming to provide guidance for further improvement of tandem devices.