Semiconductor and semiconductor-metal heterostructural nanocrystals (HNC) have drawn an increased amount of attention owing to their superior optoelectronic properties and potential applications. Herein we report a study of pressure- induced structural and optical evolution of FAPbI3 hybrid organic−inorganic perovskite nanocrystals and pressure-driven processing of HNC superlattices self-assembled from quantum-dot-Au (QD-Au) satellite-type HNCs into monodispersive hetero-dimers and hetero-rods. Using a synchrotron-based X-ray scattering technique coupled to in situ absorption and photoluminescence spectroscopies, the structural and optical evolution were successfully monitored during the whole pressure cycle. Our results show that FAPbI3 NCs exhibit a wide range of band-gap tunability (1.44 to 2.17 eV) as a function of pressure and QD-Au HNC-SLs underwent a permanent structural transformation at both the atomic- and the meso-scales during the pressure processing. The intra particle coalescence of Au satellites at QD surfaces transforms individual QD-Au satellite HNCs into hetero-dimers, whereas the interparticle fusion drives assembled HNCs into ordered hetero-rods arrays. The pressure synthesis of the unique nanostructures suggests the use of high-pressure-processing as a clean and fast means to controllably engineer the nanocrystals both in morphology and properties.

Pressure induced transformation of formamidinium lead halide perovskite and quantum dot gold heterostructural nanocrystals

2019 Fall National Meeting

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