A Universal Strategy to Enhance Circularly Polarized Luminescence Brightness in Chiral Perovskites
Chiral perovskites are considered as promising candidates for circularly polarized luminescence (CPL) light source, by attracting the broader scientific community for their applications in chiral optoelectronics and spintronics. However, it is still a great challenge to achieve both substantial photoluminescence asymmetry ( g CPL ) and high photoluminescence quantum yield (PLQY) simultaneously for high CPL brightness due to the limitations associated with magnetic transition dipole moments. Herein, this problem is overcome and achieve both large g CPL of 1.6×10 −2 and PLQY of 56% in chiral perovskite through the magnetic element doping strategy. The substitution of Pb 2+ ion with smaller magnetic Mn 2+ ions shrinks the crystal lattice around [MnBr 6 ] 4− octahedra, amplifying the asymmetric distortion surrounding the Mn 2+ ions. Moreover, the transition associated with Mn 2+ ions can harvest the photoexcitation energy in chiral perovskites, and its spin-flipping characteristics enable highly efficient CPL from the d–d transition on Mn 2+ energy levels. Furthermore, this magnetic element doping strategy is proven to be a universal tactic for enhancing CPL brightness as confirmed in a series of 1D- or 2D-chiral perovskites with various chiral ligands or halogens. The findings provide an in-depth understanding of the structure-property relationship in chiral perovskites toward chiral optoelectronic and spintronic applications.
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