Interplay of optoelectronic properties and solar cell performance in multidimensional perovskites

Abstract

Perovskite is an emerging material for photovoltaic application that has reached 22.7% efficiency to date. Despite its excellent properties such as defect tolerance and long carrier lifetime, the high-performing perovskite material, methylammonium lead iodide (MAPI), which has 3D structure, is still unstable. Recent studies have hinted at the possibility of shifting focus from 3D to lower dimensional perovskite structures because lower dimensional structures are more environmentally stable for a longer period than the 3D analogues. We propose a detailed study where PbI₂ is used as the backbone and A-site cations are alloyed with various combinations: methylammonium, dimethylammonium, iso-propylammonium, and t-butylammonium. We measure the perovskite solar cell devices' performance and characterize the solar absorber to understand the optoelectronic properties. It is shown that the addition of large A-site cations change the structures into lower dimension, which increases the bandgap and decreases device performance properties such as efficiency, open-circuit voltage, and short-circuit current. Hence, there is a trade-off between having more stable perovskite and high-performance cell in using large A-site organic cations.