Dimensional modulation on the spin-spin and electron-phonon couplings in Mn doped cadmium chlorides framed by different phenylenediamine isomers

Low-dimensional metal halides are promising photoelectric materials due to outstanding luminescence efficiency, diverse components and stability. Customizing and precisely adjusting their microscopic interactions and optical response is crucial for expanding their potential applications. Doping strategies, especially those involving transition metal (TM) ions with spins, have been widely employed to reach above target. In this study, two isomers of phenylenediamine were selected as cations to regulate the dimensions of two organic-inorganic hybrid cadmium halides with varied dimensionality through organic π-π stacking interaction, spin-spin coupling and electron-phonon coupling. In two-dimensional structures the phonon zone folding effect expands the electron-phonon coupling range, which can lead to magnetic polarons covering different layers with the multi-phonon coupling promotion, although local excitons are preferentially present in a polyhedral of one-dimensional or two-dimensional structures. The different binding energy and size of the magnetic polaron within a layer (chain) determine its temperature of the highest emission intensity and related PL efficiency. Moreover, the antiferromagnetic (AFM) coupling between layers (chains) can also affect the range and coefficient of electron-phonon coupling, thereby influencing the emission efficiency. Therefore, the magnetic coupling and electron-phonon interaction in varied structures contribute to the modulation of the spatial zone, binding energy and transition processes of the polaronic exciton states in low-dimensional metal halides, which holds great significance for further material designs, luminescence optimizations and applications.