3D Printing of Arbitrary Perovskite Nanowire Heterostructures

Abstract Deterministic integration of arbitrary semiconductor heterostructures opens a new class of modern electronics and optoelectronics. However, the realization of such heterostructures continues to suffer from impracticality, requiring energy‐ and labor‐intensive, time‐consuming fabrication processes. Here a 3D printing approach to fabricate freestanding metal halide perovskite nanowire heterostructures with a high degree of control over shape and composition is demonstrated. These features arise from freeform guiding of evaporation‐driven perovskite crystallization by a femtoliter precursor meniscus formed on a printing nozzle. By using a double‐barreled nanopipette as a printing nozzle, “all‐at‐once” heterostructure fabrication is achieved within seconds. The 3D‐printed perovskite nanowire heterojunctions with multiple emission colors provide exciting optical functionalities such as programmable color mixing and encryption at the single nanopixel level. This “lithography‐free” additive approach opens up the possibility to freely design and realize heterostructure‐based devices without the constraints of traditional manufacturing processes.