Room-Temperature Collective Quantum Emission Mediated by Wannier-Mott Excitons in CsPbBr3 Nanowires

Abstract

Room-temperature collective quantum emission (RT-CQE), enabled by many-body interactions and phase-synchronized dipole oscillations, offers a promising path for scalable quantum photonics. Here, superfluorescence (SF) is demonstrated in CsPbBr3 perovskite nanowires (NWs), facilitated by Wannier-Mott excitons with spatially delocalized wavefunctions and strong dipole-dipole interactions. The intrinsic quasi-1D geometry and occasional bundling promote preferential dipole alignment along the NW axis, enabling long-range phase coherence. Key experimental signatures, photon bunching with g 2(0) approximate to 2, femtosecond-scale coherence time (approximate to 88 fs), and ultralow excitation threshold (approximate to 210 nJ-1 cm2), confirm the onset of SF at ambient conditions. Ultrafast spectroscopy reveals bandgap renormalization, state filling, and exciton-phonon coupling, consistent with collective excitonic behavior mediated by delocalized states. Unlike other RT-SF mechanisms based on polarons or electron-hole liquids, the system exploits directional dipole alignment and exciton delocalization in quasi-1D NWs, allowing coherent emission without the need for high excitation densities or complex structural ordering. These findings demonstrate that CsPbBr3 NWs can sustain RT-SF driven by exciton delocalization and directional dipole coupling, providing a new physical platform for coherent light generation under ambient conditions.