One‐step Centimeter‐Scale Growth of Sub‐100‐nm Perovskite Single‐Crystal Arrays in Ambient Air for Color Painting

Halide perovskite single crystals have demonstrated enormous potential for next-generation integrated optoelectronic devices. However, there is a lack of a facile method to realize the controllable growth of large-scale, high-quality, and high-resolution perovskite single crystal arrays on diverse types of substrates, which hinders their application in practical scenarios. Here, a one-step wettability-guided blade coating approach is reported for the rapid in situ crystallization of large-scale, multicolor, and sub-100 nm perovskite single-crystal arrays in the ambient environment. By this strategy, the physical dimensions of perovskite single crystals can be precisely regulated from 90 to 260 nm, with a size variation coefficient < 10% and an area of over 900 mm². All three typicalhalogen perovskites for multi-color luminescence, CsPbX₃ (X = Cl, Br, I) and their mixtures (Cl/Br or Br/I systems), are appliable to this fabrication process through the demonstration of complex RGB patterns with remarkable photoluminescence properties. Moreover, various rigid substrates such as silicon oxide (SiO₂), silicon (Si), and glass can also be used to construct the wettability-constrast templates where perovskite crystal nucleate and grow. After that, the perovskite single-crystal arrays or complex patterns can be transferred onto flexible substrates, for instance, COC. This method combines convenient solution processing with conventional photolithography to prepare the high-resolution, large-area, and superior-quality perovskite single crystal arrays in a high-throughput manner, showing great potential in the integration of perovskite nano-optoelectronic devices and chips.