论文部分内容阅读
Perovskite solar cells (PSCs) developed great potential to make photovoltaic power generation systems more cost effective ascribed to the high-power conversion efficiency,low material cost,and easy fabrication process.Alloyed A-site cations located in PbI6 octahedron play decisive roles in the crystal structure,band gap,and stability,as well as lattice strain of perovskite layer.Herein,we systematically studied the regulation of A-site cations based on methylamine gas healing technology and elaborated the chemical behavior of different A-site cations in the healing procedure in detail.We have found that guanidinium cation (GA+) was stable and tolerant to methylamine gas.Based on methylamine gas healing technology,we prepared perovskite solar cells with triple A cations system (MA0.8FA0.1GA0.1PbI3) and achieved an efficiency over 22%.In this system,MA ion served as the foundation to realize defect healing process,FA ion formed a 1D passivation layer,and GA ion remained incorporated in the lattice lowering lattice strain and stabilizing the 3D framework,where three cations are complemented each other according to their own functions.Our findings open up new avenues for material system selection based on methylamine gas healing technology and preparation of efficient and stable PSCs.