Room‐Temperature Collective Quantum Emission Mediated by Wannier–Mott Excitons in CsPbBr 3 Nanowires

Journal article

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 g2(0) ≈2, femtosecond‐scale coherence time (≈88 fs), and ultralow excitation threshold (≈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.

Authors: Alanazi, M; Jana, A; Nguyen, DA; Cho, S; Park, S

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Small Science
• Article number: e202500400
• Publication date: 2025-09-29
• DOI: 10.1002/smsc.202500400
• EISSN: 2688-4046
• ISSN: 2688-4046
• Language: English
• Keywords: superfluorescence; room‐temperature quantum optics; collective quantum emissions; cesium lead bromide nanowires; Wannier–Mott excitons