Acquiring High-Performance and Stable Mixed-Dimensional Perovskite Solar Cells by Using a Transition-Metal-Substituted Pb Precursor

In recent years, as the most promising photovoltaic technology, lead halide perovskite solar cells (PSCs) have become a research hotspot owing to their super-high power conversion efficiency (PCE) and simple preparation method. However, the toxicity of lead and instability under high humidity and temperature greatly affects their further development. In this study, we investigated three kinds of non-toxic transition metal cations (Zn2+, Mn2+, and Ni2+) at 3% to partially substitute lead cations and form mixed-dimensional (MD) perovskites. Among these transition metals, Zn2+ is the most suitable to replace Pb2+ and Zn-MD perovskite device exhibits the best PCE of 18.35%. In addition, we further studied the humidity and heat stability of methylammonium lead iodide (MA), Zn-MD, Mn-MD, and Ni-MD perovskite devices. Upon exposure to about 50% relativity humidity (RH) for 800h, the MA and three MD devices, respectively, maintain 30%, 81%, 80%, and 74% of their original PCE. After aging at 60 degrees C for 100h, the PCEs of the four PSCs retain 40%, 84%, 85%, and 76% of their starting values, respectively. The results show that the three MD perovskite devices have high humidity and heat stability and using transition-metal-substituted Pb can gain long-term stability and reduced toxicity of PSCs.