Structural Origin of Enhanced Circularly Polarized Luminescence in Hybrid Manganese Bromides.

Chiral hybrid metal halides with a high dissymmetry factor (g _lum ) and a superior photoluminescence quantum yield (PLQY) are promising candidates for circularly polarized luminescence (CPL) light sources. Here, we report eight new chiral hybrid manganese halides, crystallizing in the non-centrosymmetric space group P2 ₁ 2 ₁ 2 ₁ and showing intense CPL emissions. Oppositely-signed circular dichroism (CD) and CPL signals are detected according to the R- and S-configurations of the chiral alkanolammonium cations. Time-resolved PL spectra show long averaged decay lifetimes up to 1 ms for (R-3-quinuclidinol)MnBr ₃ (R-1). The g _lum of polycrystalline samples for coordinated structures (23×10 ^-3 ) is more than doubled compared with the non-coordinated ones (8.5×10 ^-3 ), due to the structural variations. R-1 exhibit both a high g _lum and a high PLQY (50.2 %). The effective chirality transfer mechanism through coordination bonds, with strongly emissive Mn ^II centers, enables a new class of high-performance CPL materials.
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