Facet Engineering for Manipulated Photoluminescence Blinking from Perovskite Nanocrystals

Photoluminescence (PL) blinking of nanoparticles, while detrimental for their optoelectronic and imaging applications, can be beneficial for next-generation displays, especially when blinking is precisely controlled by reversible electron/hole injection from an external source. Efforts have been made toward forming a definite charged state to understand trion-induced PL-blinking by electrochemical charging of nanoparticles, which may lead to greater control over PL-blinking. A key parameter deciding the success of controllable PL-blinking from nanoparticles is their affinities towards photo-oxidation and/or photo-reduction. This work shows that facet engineering renders perovskite nanocrystals (PNCs) with distinct blinking properties based on their number of facets. Interestingly, the off-duration (τ_off) in the PL intensity time-trace and the fraction time spent in the off-state of a surface-immobilized PNC enhance as the number of facets increases from six (cube-PNC) to twelve (dodecahedron-PNC) and, to twenty-six (rhombicuboctahedron-PNC). Our observation suggests a greater affinity for photo-charging of extra faceted PNCs.