In bulk semiconductors, luminescence is treated under the electric dipole approximation, where magnetic dipole (MD) and higher-order multipolar transitions are assumed negligible under parity selection rules. However, two-dimensional (2D) metal-halide perovskites frequently exhibit anomalous low-energy emission signatures arising from out-of-plane oriented MD transitions. As these transitions are nominally disallowed due to parity selection rules, we aim to identify the symmetry-breaking mechanisms that activate these forbidden emissive pathways. Here, we demonstrate that anomalous MD emission in 2D HOIPs is correlated with the deviation of interoctahedral bond angles from 180°. Beyond establishing a fundamental structure–property link, this finding equips researchers with a synthetic design rule for harvesting multipolar emission from 2D perovskites for next-generation optoelectronic devices. Our findings also reveal that modular metal cation substitution─specifically replacing Pb with Sn─provides a robust mechanism for tuning forbidden emission intensity through lone-pair-driven dynamic structural distortions.
The intrinsic out-of-plane polarity of two-dimensional (2D) Janus materials provides a natural route to regulate photogenerated carrier dynamics. Here, we study electronic structures, stability, and carrier recombination dynamics of five-atomic-layer Janus group-III chalcogenide monolayers with chemical formulas MN...
Yi-Fan Wu, Shi-Qi Li, Yuee Xie et al.· Chinese Physics B· 0 citations
Two-dimensional tin perovskites are attracting increasing attention for coherent light emission, yet the impact of organic cations on their properties remains poorly understood. Here, we compare the Ruddlesden–Popper (RP) butylammonium tin iodide (BA2SnI4) and Dion–Jacobson (DJ) 1,4-diammoniobutane tin iodide (DABSnI4)...
Francesca Canestra, Nurgul Sarsembek, Ya-Rong He et al.· Journal of the American Chem...· 0 citations
Vacancy-ordered double perovskites of the formula A2MX6 (where A is a +1 cation, M is a +4 metal, and X is a halide ion) offer improved ambient stability over other AMX3 perovskites and reduced toxicity compared to those containing lead. Furthermore, their broad, highly Stokes-shifted emission makes them particularly w...
Alexandra Brumberg· Physical Chemistry of Semico...· 0 citations
Most zero-dimensional hybrid metal halides enable emission in the first near-infrared (NIR-I) region (650–950 nm), and the shorter wavelengths result in poor photon penetration depth. Here, we report the observation of an NIR-II emission signal (band gap = 1.13 eV) from a (BTBAC)2Sb2Cl8 single crystal at room tempera...
Jia Jiang, Wei-Hao Wang, Ya-Ge Ji et al.· Chemistry of Materials· 0 citations
Perovskite nanocomposites have emerged as an effective strategy to overcome instability of metal‐halide perovskites (MHPs) by embedding nanocrystals (NCs) within host matrices while preserving their optoelectronic properties. However, this approach often results in morphologically heterogeneous systems with broad s...
Miriam Minguez-Avellan, A. Marunchenko, Víctor Sagra-Rodríguez et al.· Advanced Optical Materials· 0 citations
