Non‐Invasive Epitaxy of Programmable Perovskite Single‐Crystalline Heterostructure Arrays

Perovskite single crystal arrays combine the advantages of low defect density, coherent lattice orientation and multiplexed channels, which offer great potential across various fields ranging from energy conversion and signal detection to flexible electronics. However, the poor regularity in the morphology, composition, and heterophase of perovskite arrays poses a major challenge in manipulating the optical and electronic characteristics. Here, we demonstrate a non‐invasive general epitaxial growth approach for fabricating perovskite single‐crystalline heterostructure arrays with programmable dimensions, geometry, and composition on various substrates. The solvation structure during array epitaxy is meticulously manipulated by co‐solvents, which minimizes the detrimental nucleus dissolution and favors the formation of well‐defined and uniform perovskite heterostructure arrays. The electronic properties of the fabricated perovskite arrays approach those of bulk single crystals with a carrier mobility of 18.29 cm 2 V – 1 s −1 and a trap density of 5.76 × 10 12 cm −3 . Using these heterostructure arrays, micro‐LED devices have been fabricated exhibiting unique electrochromic function. The programmable production of perovskite heterostructure arrays offers a well‐defined platform for fundamental studies and device integration of perovskite‐based optoelectronics.