Near-infrared absorption enhancement for perovskite solar cells via the rear grating design

Optical management and design is one of the most effective methods to unlock the full potential of photocurrent density and power conversion efficiency for perovskite solar cells (PSCs). However, the common-used optical designs are still limited by the near-infrared response. Here, we proposed an effective optical structure in PSCs by texturing the rear-side perovskite layer with a rectangular grating to promote the optical response in the near-infrared region. Through the comprehensive numerical simulations, the new design under the optimized structural configuration shows an improved photocurrent density, i.e., from 22.75 (flat structure) to 23.72 mA/cm². We confirm that the optical absorption enhancement occurs at the near-infrared region by the wavelength-dependent absorption and reflection spectra. Besides, the light-trapping mechanism was clarified by the comprehensive analysis of the electric field distributions. Moreover, PSCs having the rear-grating design demonstrate the superior optical performance compared to that of flat design in the varied incident angles. Our simulation results displayed in this study provide an easy scheme to promote the optical absorption in near-infrared region.