Progress, challenges, and further trends of all perovskites tandem solar cells: A comprehensive review

Metal halide perovskites (MHPs) with tunable bandgaps and strong light absorptions in the broad spectral range of ∼ 1.2–2.3 eV make them suitable candidates as light absorber in tandem photovoltaic (PV) devices. This review presents the latest progress and limitations of all perovskite tandem solar cells (AP-TSCs) with different configurations. As of today, the power conversion efficiency (PCE) and stability of reported AP-TSCs have not yet met the requirements for commercial products, mainly due to prominent defect activities in both absorbers of top wide bandgap (WB) and bottom narrow bandgap (NB) metal halide perovskites (MHPs). In this paper, we critically examine the unique instabilities and energy loss channels in WB-MHPs and NB-MHPs, as well as discuss the corresponding strategies to suppress them. We also discuss the effect of the interconnecting layer on the preparation of high-quality light absorber by a solution method. Moreover, we analyze in detail the unique requirements and methods of device packaging to improve the stability of AP-TSCs. Finally, we offer new viewpoints on the major challenges, favorable circumstances, and heuristic perspectives for future studies.