Bifacial perovskite/silicon heterojunction tandem solar cells based on FAPbI3-based perovskite via hybrid evaporation-spin coating
Mohammad Reza Golobostanfard, Mostafa Othman, Deniz Türkay, Kerem Artuk, Xin Yu Chin, Mounir Mensi, Daniel A. Jacobs, Quentin Jeangros, Christian M. Wolff, Aïcha Hessler‐Wyser, Christophe Ballif
Abstract
Combining the two technologies of tandem solar cells and bifacial solar cells has a great potential to maximize energy harvesting while minimizing material and surface usage. Mid-bandgap perovskites (1.50–1.60 eV) are important for fulfilling current matching in bifacial perovskite/silicon heterojunction tandem solar cells. Herein, efficient (>20 %) and stable planar FAPbI 3 -based perovskite (1.54 eV) solar cells have been fabricated via a hybrid evaporation-spin coating process . X-ray diffraction and electron microscopy data reveal the formation of highly crystalline (001) perovskite domains. The fabricated high-quality perovskite films lead to a more homogenized contact potential difference at the film surface and a reduction in non-radiative losses, resulting in a quasi-Fermi-level splitting (half-cell) of 1.16 eV, rendering 120 mV non-radiative losses. Transferring these films into tandem devices atop single-side textured silicon heterojunction bottom cells, we obtain an efficiency of >24 % under AM1.5 G illumination for monofacial devices with an active area of 1.21 cm 2 . Furthermore, the bifacial devices generate >27 mW cm −2 power output with 15 % rear illumination fraction.