Deterministic Fabrication of Arbitrary Perovskite—Perovskite Heterostructures

Heterostructures play a crucial role in the semiconductor industry as they offer unique optoelectronic properties. However, the conventional methods used for fabricating heterostructures involve specialized and costly processes such as chemical vapor deposition, epitaxial growth, or e-beam deposition. Halide perovskites have emerged as a promising material for various optoelectronic applications due to their tunable bandgap, high carrier mobility, and solution processability. In recent years, considerable efforts have been made to develop perovskite heterostructures using vapor phase techniques. However, the development of a universal solution processed approach for fabricating multilayer perovskite heterostructures has remained a challenge. To address this, we conducted detailed perovskite-solvent interaction studies to gain a deeper understanding of perovskite solvation dynamics. In this study, we present a solvation-based approach to synthesize perovskite seed solutions, enabling the fabrication of 2D/3D, 3D/2D, and even 3D/3D heterostructures. This approach allows us to create an arbitrary number of layers with any perovskite phase while maintaining high optoelectronic quality and scalability. To demonstrate the universality of our approach, we successfully created formamidinium lead iodide (FAPbI3)/Dion-Jacobson 2D (3D/2D) perovskite and methylammonium lead iodide (MAPbI3)/MAPbI3 (3D/3D) heterostructures. We validated the quality and characteristics of these heterostructures through optoelectronic and cross-sectional analyses. The resulting heterostructures had the desired phase (n-value specificity) and significantly enhanced durability relative to the FaPbI3 control. Grazing incident wide angle x-ray scattering (GIWAXS) analysis indicated that (FAPbI3)/Dion-Jacobson bilayers had triple the durability (monitored via FAPbI3-δ phase formation) as compared to the FAPbI3 control. High quality perovskite n-i-p devices with >24% power conversion efficiency of the (FAPbI3)/Dion-Jacobson bilayers were fabricated compared to the 22% FAPbI3 controls. The introduction of this universal approach marks a significant milestone in solution processed heterostructures, extending its applicability beyond perovskites to the broader field of semiconductors. This advancement opens up new possibilities for the synthesis of high-quality, scalable heterostructures, revolutionizing the semiconductor industry.