Sb-Doped Metal Halide Nanocrystals: A 0D versus 3D Comparison

[Image: see text] We synthesize colloidal nanocrystals (NCs) of Rb(3)InCl(6), composed of isolated metal halide octahedra (“0D”), and of Cs(2)NaInCl(6) and Cs(2)KInCl(6) double perovskites, where all octahedra share corners and are interconnected (“3D”), with the aim to elucidate and compare their optical features once doped with Sb(3+) ions. Our optical and computational analyses evidence that the photoluminescence quantum yield (PLQY) of all these systems is consistently lower than that of the corresponding bulk materials due to the presence of deep surface traps from under-coordinated halide ions. Also, Sb-doped “0D” Rb(3)InCl(6) NCs exhibit a higher PLQY than Sb-doped “3D” Cs(2)NaInCl(6) and Cs(2)KInCl(6) NCs, most likely because excitons responsible for the PL emission migrate to the surface faster in 3D NCs than in 0D NCs. We also observe that all these systems feature a large Stokes shift (varying from system to system), a feature that should be of interest for applications in photon management and scintillation technologies. Scintillation properties are evaluated via radioluminescence experiments, and re-absorption-free waveguiding performance in large-area plastic scintillators is assessed using Monte Carlo ray-tracing simulations.