Nanopillar arrays of mesoporous Bi2Se3 and CuInSe2 in layer-based perovskite solar cells

The improvement of light trapping inside the active layer of perovskite solar cells (PSCs) was numerically investigated. The light absorption probability was improved by incorporating periodic arrays of mesoscopic electron-transporting layer into the absorber layer (CH₃NH₃PbI₃) of the PSCs. Accordingly, chalcopyrite (CuInSe₂) and bismuth selenide (Bi₂Se₃) were introduced in the form of hexagonal pillars with an optimum radius of 35 nm and a height of 292 nm. It was found that the proposed PSCs can significantly extend the broadband light absorption from the visible spectrum to the near-infrared (NIR) region compared to planar PSCs that have an identical active layer thickness. After optimization, the PSCs based on MP-CuInSe₂ and MP-Bi₂Se₃ showed the best performance with an enhancement of respectively 32% and 54 % in the photocurrent density, (with values of 29.94 and 34.93 mA.cm⁻²), as compared to the planar PSC (with a photocurrent density of 22.69 mA.cm⁻²). This enhancement resulted from a more effective carrier transport due to the mesoscopic structures.