High-Resolution Fabrication of Customized Patterned Gradient Perovskite Films via Motion-Programmed Steam Jet

Patterned gradient perovskite structures, featuring spectrally graded and continuously tuneable bandgaps, are promising for hyperspectral sensing. However, existing manufacturing strategies are constrained by sluggish reaction kinetics, poor film uniformity, and limited localized controllability, making it challenging to achieve high-resolution and programmable gradient architectures. Here, we demonstrate a high-precision, motion-programmed steam jet strategy, which simultaneously controls high-resolution patterning and compositional gradients in perovskite films. By optimizing the steam jet platform, including the mixing-chamber angle and the stabilization-tube length-to-diameter ratio, a stable and spatially confined vapor-treatment field was established for localized halide exchange. Through digitally programmed trajectories, the local vapor-exposure time can be precisely controlled, allowing the customized patterned gradient construction of perovskite films tailored to diverse optoelectronic applications. After optimizing the substrate morphology and the steam-jet processing parameters, the customized patterned gradient perovskite films (CusGrad-PPFs) exhibited a spectral-gradient slope of 1.31 nm mm-1, with a spatial resolution of 76.4 μm (defined on the basis of a typical spectrometer measurement accuracy of 0.1 nm). EDS line-scan analysis yielded a mean 10-90% patterned-boundary width of 344.4 μm. Furthermore, a gradient position sensor was developed as a proof of concept, achieving an average resolution of 2.4 mm nm-1. This strategy provides a novel route for the high-precision and customizable fabrication of gradient perovskite films and establishes a proof-of-concept basis for spectrally encoded position sensing.