Precisely Control Light Field by the Grating‐Structured Nanoimprinting Technology Toward High‐Efficiency Perovskite Solar Cells

The power conversion efficiency (PCE) of the perovskite solar cell (PSC) is constrained by the Shockley-Queisser (S-Q) limit. To exceed this limit, one promising method is integrating light-trapping structures into PSCs to improve the interaction between incident light and the active layer. Herein, the impact of grating structures on PSCs is systematically investigated from three aspects, including light field simulation, experimental verification, and performance analysis. The simulation results demonstrate that the grating structure modifies the light propagation path, thereby optimizing the spatial distribution of the optical field within the perovskite layer. This modification significantly enhances the interaction between the perovskite and incident photons, leading to improved light absorption. Experimental validation confirms that the grating structures significantly enhance light absorption of PSCs, leading to increasing the short-circuit current density from 23.89 to 25.38 mA cm^-2 and improving the PCE from 22.45% to 24.63%. Furthermore, the imprinting process promotes homogeneous crystal growth, improves perovskite film crystallization, and reduces the defect density of film. Overall, the work highlights the enormous potential of grating structures in enhancing the PCE of ultrathin PSC (PVK under 500 nm) and decreasing the cost simultaneously, which provides a way for the commercialization of efficient and stable PSCs.