Programmable, High‐resolution Printing of Spatially Graded Perovskites for Multispectral Photodetectors

Abstract Micro/nanostructured perovskites with spatially graded compositions and bandgaps are promising in filter‐free, chip‐level multispectral, and hyperspectral detection. However, achieving high‐resolution patterning of perovskites with controlled graded compositions is challenging. Here, a programmable mixed electrohydrodynamic printing (M‐ePrinting) technique is presented to realize the one‐step direct‐printing of arbitrary spatially graded perovskite micro/nanopatterns for the first time. M‐ePrinting enables in situ mixing and ejection of solutions with controlled composition/bandgap by programmatically varying driving voltage applied to a multichannel nozzle. Composition can be graded over a single dot, line or complex pattern, and the printed feature size is down to 1 µm, which is the highest printing resolution of graded patterns to the knowledge. Photodetectors based on micro/nanostructured perovskites with halide ions gradually varying from Br to I are constructed, which successfully achieve multispectral detection and full‐color imaging, with a high detectivity and responsivity of 3.27 × 10 15 Jones and 69.88 A W −1 , respectively. The presented method provides a versatile and competitive approach for such miniaturized bandgap‐tunable perovskite spectrometer platforms and artificial vision systems, and also opens new avenues for the digital fabrication of composition‐programmable structures.