Growth of van der Waals Halide Perovskites within the Interlayer Spacings of Mica

Two-dimensional hybrid organic–inorganic perovskites (2D-HOIPs) have been extensively researched for use in solar cells as well as optoelectronic devices over the past few years. Controllable growth of single-crystalline 2D-HOIP thin films has been regarded as a key component for the development of high-performance end devices. Here, we report a solution-based method for the growth of 2D-HOIPs using muscovite mica as a van der Waals substrate that yields millimeter-scale perovskite flakes. Interestingly, the grown 2D-HOIP flakes lie embedded within the interlayer spacings of muscovite mica. We find that such 2D-HOIP flakes buried in mica demonstrate enhanced photostability in comparison to conventional 2D-HOIP flakes. Such liquid-phase growth in the interlayer spacings of van der Waals substrates opens a new avenue for developing novel material structures for designing optoelectronic devices.