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

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, we present a programmable mixed electrohydrodynamic printing (M-ePrinting) technique 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 programmably varying driving voltage applied to a multi-channel 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 our knowledge. Photodetectors based on micro/nanostructured perovskites with halide ions gradually varying from Br to I were 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, respectively. Our 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. This article is protected by copyright. All rights reserved.