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 1µm, 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 × 1015 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.