Giant Room‐Temperature Chiral Quantum Emission ( g _lum >0.4) From Lattice‐Symmetry‐Broken Perovskites

Abstract Chiral quantum emitters attract significant interest for their unique non‐reciprocal photon‐mediated properties and potential in quantum operations. Achieving chiral quantum emission has traditionally required sophisticated techniques like high magnetic fields or cryogenic temperatures, and room‐temperature circularly polarized luminescence (CPL) from individual quantum emitters is rarely reported. Here, it is shown that certain CsPbI ₃ perovskite quantum dots (PQDs) exhibit both room‐temperature quantum emission and intrinsic CPL. Density functional theory (DFT) reveals that structural helicity and defects in PQDs induce band splitting, directly linking broken lattice symmetry to the observed chiroptical activity. By synthesizing PQDs with irregular shapes and reduced crystallinity, an unprecedented luminescence dissymmetry factor ( g _lum ) is achieved up to 0.41 without sacrificing the bright single‐photon emission properties of PQDs. These findings establish PQDs as highly promising room‐temperature chiral quantum emitters, paving the way for their application in scalable chiral quantum nanophotonics and quantum manipulation.