Transferable High-Quality Inorganic Perovskites for Optoelectronic Devices by Weak Interaction Heteroepitaxy

Transferable semiconductors with superior light-emitting properties are important for developing flexible and integrated optoelectronics. However, finding such a qualified candidate remains challenging. Here, we report the fabrication of transferable high-quality CsPbBr₃ single crystals on a highly oriented pyrolytic graphite (HOPG) substrate via weak interaction heteroepitaxy for the first time. Semi-quantitative kinetic analysis based on the classical nucleation theory well accounts for the van der Waals (vdW) epitaxial growth process of perovskite on the HOPG substrate. The density functional theory calculations illustrate the bonding nature of the interface and predict the Volmer-Weber growth mode in vdW epitaxy, which is consistent with our experimental observations. Importantly, the extremely weak vdW interaction between the perovskite and HOPG not only enables the high quality of the crystals but also endows them with the facile transferability to any foreign substrate by the mechanical exfoliation technique. Leveraging on the transferred CsPbBr₃ single crystals, the low-threshold microlasers and monolithic perovskite light-emitting diode devices are demonstrated. Our results represent a significant step toward advanced optoelectronic devices relying on the emerging perovskite semiconductors.