Design and fabrication of perovskite solar cells for tandem structures

Abstract

In this thesis, fabrication processes for making perovskite solar cells (PSCs) suitable for tandem structures are described. We find that different conditions of fabrication significantly affect the perovskite absorber film properties and power conversion efficiency (PCE) of PSCs. To achieve the best quality, perovskite absorber films were prepared by two-step spin coating from PbI2 and CH3NH3I (MAI) precursors, and solar cell yielded a maximum PCE of 17.2% and 15.4% for a normal and an inverted PSCs, respectively. These PSCs can be applied to the design and fabrication of tandem solar cells (TSCs) that consist of PSCs as a top subcell and copper indium gallium diselenide (Cu(In, Ga)Se2 or CIGS) solar cells as a bottom subcell. In this thesis, TSCs are fabricated as both two-terminal (2T) and four-terminal (4T) tandem solar cells. Both normal and inverted perovskite, which act as a top subcell, are developed with several strategies. For a 4T tandem solar cell, a PCE of 22.6% and 17.6% are achieved with the top subcells being the normal and inverted PSCs, respectively.