Profiling Light Absorption Enhancement in Two-Dimensional Photonic-Structured Perovskite Solar Cells

The light absorption behavior in two-dimensional (2-D) photonic-structured active layer in lead halide perovskite solar cells (PSCs), induced by a 2-D photonic-structured TiO2 nanobowl electron extraction layer, is investigated systematically by the finite element method. The numerical results indicate that light absorption in the 2-D photonic-structured PSCs is apparently more favorable for efficient cell operation when compared to that of the planar control device having a perovskite layer thickness less than 300 nm. For optimal 2-D photonic-structured PSCs with a 100 nm thick perovskite layer, the integrated absorption efficiency reaches 65.7% over the wavelength range from 350 to 800 nm at normal incidence considering AM 1.5G solar irradiation, with enhancement of 18.4% with respect to the control cell, and being 88.3% of that of the planar PSC with 300 nm-thick perovskite layer by only 1/3 perovskite material consumption. The detailed field distribution investigations reveal that the great enhancement of light absorption in the long wavelength region is attributed to the collective impact of the different photon and plasmonic modes and their mutual coupling. This work paves the way to realize the low-cost, high-efficiency ultrathin PSCs.