CsPbBr Superstructures with Circularly Polarized Photolumines-Cence Obtained by the Self-Assembly and Annealing of Nanoclusters.

We report a two-step approach to fabricate CsPbBr superstructures with strongly circularly polarized photoluminescence by self-assembly of nanoclusters on a substrate, followed by their annealing. In the first step, the nanoclusters self-assemble upon solvent evaporation, a process that forms mesoscopic superstructures whose geometrical arrangement at the μm-scale confers them optical chirality. In the second step, mild annealing of such superstructures induces the coalescence of the nanoclusters, accompanied by a continuous red shift of the photoluminescence up to 530 nm, with preservation of the μm-scale wires bundles and the chiral properties of the sample (g=0.1). The successful chirality transfer from the initial nanoclusters assemblies to these final CsPbBr superstructures provides a convenient way to obtain circularly polarized emitters.