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Mixed‐dimensional (MD) organic–metal halide hybrids (OMHHs) provide an emerging platform for integrating distinct structure‐dependent optical and magnetic behaviors within a single crystalline phase. While the photophysical properties of conventional low‐dimensional (LD) OMHHs have been widely studied, organic–inorganic hybrids that combine multiple molecular‐level dimensionalities remain largely underexplored. Here, we report a structurally unique MD diammonium manganese(II) bromide hybrid, (TMPDA)3(Mn2Br6)(MnBr4)2(TMPDA = N,N,N′,N′‐tetramethyl‐1,3‐propanediammonium), which simultaneously incorporates one‐dimensional (1D) [Mn2Br62−]∞chains and zero‐dimensional (0D) MnBr42−tetrahedra within a single crystalline framework. This architecture enables two optical centers to coexist in the same material, yielding excitation‐dependent dual emissions from both the 1D chains and 0D tetrahedra with high photoluminescence quantum efficiencies (PLQEs) of up to 62%. Magnetic measurements reveal weak antiferromagnetic interactions along the 1D chains, arising from Mn···Mn superexchange mediated by bridging bromides. These findings highlight the opportunities offered by MD OMHHs to expand structural and functional tunability beyond traditional LD hybrids, opening new directions for designing multifunctional materials with coupled optical and magnetic properties.
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This content will become publicly available on April 16, 2027
Highly Anisotropic Quasi‐Direct Organic Metal Halide Hybrids: A Platform for Polarization‐Sensitive Optoelectronics
Low‐dimensional organic–inorganic metal halide hybrids (OMHHs) exhibit remarkable optical properties and enhanced environmental stability. We investigate a 1D OMHH with formula C4N2H14PbBr4, consisting of Pb–Br chains separated by organic cations, which shows a large Stokes shift (0.83 eV) and broadband emission. Through first‐principles calculations and polarized Raman spectroscopy, we characterize the material's vibrational properties and identify the specific phonon modes that drive exciton self‐trapping. Our novel GW/Bethe‐Salpeter equation force formalism reveals that low‐frequency phonons (100 cm−1, primarily involving Pb–Br motions) couple strongly with excitons, with a remarkably high Huang‐Rhys factor of 137 ± 4, and gives a pathway for ultrafast structural analysis during the absorption process. This phonon‐exciton coupling mechanism explains the material's broadband emission and provides a pathway for controlling optical properties through vibrations and for tuning vibrations through optical excitations. The material also exhibits highly anisotropic optical properties and electronic transport, with bands that are dispersive along the Pb–Br chains but nearly flat in perpendicular directions, resulting in direction‐dependent electrical conductivity that is calculated to be an order of magnitude higher along the chain direction and consistent with measurements. These combined properties make this system an excellent platform for polarization‐sensitive optoelectronic devices.
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- Award ID(s):
- 2144317
- PAR ID:
- 10680200
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Advanced Materials Technologies
- ISSN:
- 2365-709X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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