Performance analysis of highly efficient 2D/3D bilayer inverted perovskite solar cells

Photovoltaic conversion efficiency (PCE) acquired in perovskite solar cells (PSCs) is currently competitive with that of other commercial solar cells. Despite profound progress in PSCs in the last few years, achieving long term stability is considered as a prime hindrance for the commercialization of these solar cells. Recently, low dimensional perovskites have drawn extensive interests in research to improve photo-stability, however, wide bandgap limits output power of low dimensional perovskite-based solar cells. Two-dimensional/threedimensional (2D/3D) bilayer PSCs can overcome this barrier via innovation in device engineering that can retain high performance and long-term photostability simultaneously. For example, inverted p-i-n structure of 2D/3D bilayer PSCs has drawn enormous interests in recent years due to cost-effectiveness, low temperature processing, and inhibited hysteresis characteristics. In this report, we present a numerical modeling approach to optimize the performance of an inverted 2D/3D bilayer PSC with a novel device architecture: ITO/NiOx/ BA2MAn-1PbnI3n+1/MAPbI3/ZnO/Al. Perovskite materials with thickness of -900 nm (BA2MAn-1PbnI3n+1(200 nm)/MAPbI3 (700 nm)) and defect density of 2 x 1014 cm-3 yields best cell efficiency, that is up to -24.75%. Further optimization of electron transport layer and hole transport layer along with their donor and acceptor density level leads to 2.56% increase in the efficiency, that is from -23.53% to -24.75%. Our estimation suggests that incorporating 2D BA2MAn-1PbnI3n+1 perovskite into 3D MAPbI3 perovskite yield high throughput and simultaneously minimize the fabrication cost for active absorber layer in inverted PSCs.