2019/01/16 by Ryan A. DeCrescent, DeCrescent, Ryan A., Naveen R. Venkatesan +17 · 1 citation
Engineering · Materials Science · #Conducting polymers and applications #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Perovskite Materials and Applications #Quantum Dots Synthesis And Properties
paper · pdf · doi:10.48550/arxiv.1901.05136
openalex publication_date 2019/01/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Light-matter interactions in semiconductor systems are uniformly treated\nwithin the electric dipole (ED) approximation, as multipolar interactions are\nconsidered "forbidden". Here, we demonstrate that this approximation\ninadequately describes light emission in novel two-dimensional hybrid\norganic-inorganic perovskite materials (2D HOIPs) --- a class of solution\nprocessable layered semiconductor with promising optoelectronic properties.\nConsequently, photoluminescence (PL) spectra become strongly dependent on the\nexperimental geometry, a fact that is often overlooked, though critical for\ncorrect optical characterization of materials. Using energy-momentum and\ntime-resolved spectroscopies, we experimentally demonstrate that low-energy\nsideband emission in 2D HOIPs exhibits a highly unusual, multipolar\npolarization and angle dependence. Using combined electromagnetic and\nquantum-mechanical analyses, we attribute this radiation pattern to an\nout-of-plane oriented magnetic dipole transition arising from the 2D character\nof the excited and ground state orbitals. Symmetry arguments point toward the\npresence of significant inversion symmetry-breaking mechanisms that are\ncurrently under great debate. These results provide a new perspective on the\norigins of unexpected sideband emission in HOIPs, clarify discrepancies in\nprevious literature, and generally challenge the paradigm of ED-dominated\nlight-matter interactions in novel optoelectronic materials.\n