Narrow Emission from Rb3Sb2I9 Nanoparticles

Metal halide perovskites have gained attention for their optoelectronic properties and are employed as the active layer in solar cells, light-emitting diodes, and photodetectors. However, the use of lead in the best-performing perovskite devices may limit their wider application. Prior reports of lead-free perovskite nanoparticles have exhibited linewidths more than twice as wide as their lead-halide counterparts, limiting their attainable color gamut. Here the solution synthesis of lead-free Rb3Sb2I9 nanoplatelets and single crystals is reported; the single crystals exhibit broad (full-width at half-maximum (FWHM) = 75 nm) photoluminescence centered at 635 nm, while the nanoplatelets exhibit narrow emission (FWHM = 21 nm) at 512 nm. The photoluminescence quantum yield of both the single crystals and nanoplatelets is low and the present demonstration of the narrowest emission among all lead-free perovskites reported to date motivates further study of how these and related materials can achieve further-enhanced brightness.