Biomimetic non-classical crystallization drives hierarchical structuring of efficient circularly polarized phosphors

Chiral emitters with high photoluminescence quantum yield are desirable for use in circularly polarized LEDs. The authors demonstrate the transfer of chirality from nanoscale copper iodide clusters to microscale chiral luminescent polycrystals by non-classical crystallization. Hierarchically structured chiral luminescent materials hold promise for achieving efficient circularly polarized luminescence. However, a feasible chemical route to fabricate hierarchically structured chiral luminescent polycrystals is still elusive because of their complex structures and complicated formation process. We here report a biomimetic non-classical crystallization (BNCC) strategy for preparing efficient hierarchically structured chiral luminescent polycrystals using well-designed highly luminescent homochiral copper(I)-iodide hybrid clusters as basic units for non-classical crystallization. By monitoring the crystallization process, we unravel the BNCC mechanism, which involves crystal nucleation, nanoparticles aggregation, oriented attachment, and mesoscopic transformation processes. We finally obtain the circularly polarized phosphors with both high luminescent efficiency of 32% and high luminescent dissymmetry factor of 1.5 x 10(-2), achieving the demonstration of a circularly polarized phosphor converted light emitting diode with a polarization degree of 1.84% at room temperature. Our designed BNCC strategy provides a simple, reliable, and large-scale synthetic route for preparing bright circularly polarized phosphors.

Automated summary

In this study, the authors demonstrate the transfer of chirality from nanoscale copper iodide clusters to microscale chiral luminescent polycrystals by non-classical crystallization, achieving efficient circularly polarized luminescence. The designed biomimetic non-classical crystallization strategy provides a simple, reliable, and large-scale synthetic route for preparing bright circularly polarized phosphors.