One-step synthesis at room temperature of low dimensional perovskite single crystals with high optical quality

Hybrid organic-inorganic perovskites have emerged among the most promising materials for optoelectronic applications thanks to the great synthetic versatility that allows tailoring their structural and photophysical properties. In the two-dimensional (2D) crystalline form, these semiconductors have multiple-quantum-well structure with stable excitonic resonances at room temperature. In this work we present an easy and effective anti-solvent crystallization method to synthesize n = 1 and n = 2 dodecylammonium (DA) lead iodide perovskite single crystals. Different synthetic conditions have been explored and general guidelines for single crystals preparation are provided revealing that gamma-butyrolactone is the best solvent for its ability to weakly coordinate Pb2+ centers and that diethyl ether is the best anti-solvent because fast diffuses into the precursors solution. We exploit the high optical quality of the synthesized perovskites to observe strong exciton-photon coupling in single-crystal waveguides, avoiding the need to embed them within mirror microcavities.