Lanthanide Double Perovskite Nanocrystals with Emissions Covering the UV-C to NIR Spectral Range

Lead halide perovskite nanocrystals (NCs) have recently drawn considerable attention in the fields of materials science and nanotechnology. However, a major drawback of these NCs is the reliance on toxic lead, which hinders widespread application. Herein, a new class of lead-free perovskite NCs, that is, lanthanide double perovskite (Ln-DP) NCs, with f-orbital-induced optical properties, is introduced. The Pr-, Ce-, Tb-, Eu-, Sm-, and Yb-based Ln-DP NCs display narrow d→f and f→f emissions ranging from the UV-C to the near-infrared spectral region. Experimental data and calculations reveal that the emissive Ln-DP NCs exhibit small molecule-like electronic absorptions: f→d atomic transitions or ligand-to-metal charge transfer transitions. Last, it is demonstrated that by alloying Ln compositions in the DP NCs, new materials with unique and improved optical properties can be obtained. These Ln-DP NCs are promising for optical sensing and lighting, and as components in optoelectronic and/or magneto-fluorescent devices.