Magnetic Transitions and Energy Transfer Processes in Sb-Based Zero-Dimensional Metal Halide Nanocrystals Doped with Manganese

Antimony-based 0-dimensional metal halides (0D-MHs) are attracting attention owing to their bright Stokes-shifted luminescence due to self-trapped excitons (STEs). One unexplored motif to expand their functionalities is to dope them with optically and/or magnetically active dopants that participate in energy-transfer schemes involving STEs. We investigated the photophysical and magnetic properties of Rb7Sb3Cl16nanocrystals doped with Mn2+ions, which introduce strong magnetism and activate their characteristic intra-d luminescence. By controlling the doping level, we optimize the STE → Mn2+energy transfer and tune the magnetic character of the NCs. Particles lightly doped with isolated Mn2+centers exhibit paramagnetic character and temperature-independent luminescence. By contrast, highly doped NCs show a clear transition to antiferromagnetic behavior at cryogenic temperatures similar to the behavior of low-dimensional manganese halides, accompanied by enhanced Mn emission due to suppressed exciton migration among the dopant subnetwork, thus pointing to an intimate link between the optical and magnetic properties also in Sb-based 0D-MHs.