Development of Perovskite Nanocrystal Superlattices for Studies of Collective Phenomena

Colloidal perovskite nanocrystals are building blocks for novel materials due to the property of nanocrystals to self-assemble into ordered structures (superlattices). Exemplified by a prototypical perovskite CsPbBr3, research into perovskite nanocrystal superlattices is motivated by reports of intriguing phenomena such as superfluorescence and superradiance.[1] Such cooperative luminescence arises from the radiative coupling due to the interactions between individual nanocrystals (e.g., dipole-dipole) and between nanocrystals and the common electromagnetic field.

Different collective behaviors are expected from superlattices made from nanocrystals of different sizes because of quantum confinement effects. In recent theoretical work, the role of nanocrystal parameters such as nanocrystal size, size distribution, and interparticle distances onto single-excitation superradiance have been explored.[2] The first step in testing the theoretical predictions is to produce and characterize superlattices with desired structural parameters. In this work, we will discuss preparing and characterizing CsPbBr3 nanocrystal superlattices made from strongly and moderately confined nanocrystals (ca. 5-6 nm and 10-11 nm, respectively), and address their prospects as platforms for experimental tests of the predicted superradiance.