Direct synthesis of high-quality perovskite nanocrystals on a flexible substrate and deterministic transfer

Solid-state perovskite nanocrystals are promising coherent light sources, as there is optical feedback within the crystal structure. In order to utilize the high performance of perovskites for on-chip applications, or observe new physical phenomena, these crystals must be integrated with pre-fabricated electronic or photonic structures. However, the material's fragility has made the deterministic transfer a great challenge thus far. Here, we report the first deterministic transfer of perovskite nanocrystals with sub-micron accuracy. Cesium lead halide(CsPbI_3) nanocrystals were directly synthesized on flexible polydimethylsiloxane(PDMS) stamps via chemical vapor deposition(CVD) and subsequently transferred onto arbitrary substrates/structures. We demonstrated the transfer of a CsPbI_3 crystalline nanoplate(NP)onto an 8 mm fiber core and achieved single-mode whispering gallery mode lasing. Our method can be extended to a variety of other arbitrary substrates(e.g., electrodes, photonic structures, micromechanical systems), laying the foundations for previously unattainable opportunities in perovskites-based devices.