Temperature-independent emission in a [(CH3)3NPh]2MnBr4 single crystal analogous to thermally activated delayed fluorescence

Journal article

We demonstrate a novel defect-mediated, thermally-activated emission mechanism in [(CH3)3NPh]2MnBr4 single crystals, driven by the coexistence of temperature-sensitive shallow traps and temperature-independent deep traps introduced by Br vacancies. Through comprehensive temperature-dependent photoluminescence (PL) and time-resolved PL measurements, combined with first-principles calculations, we reveal that the material exhibits exceptional thermal stability, retaining 67 % of its relative PL quantum yield at room temperature and achieving an absolute quantum yield of ∼38.9 % under optimal excitation conditions. The dual-component PL decay dynamics consist of a fast decay (∼hundreds of ps) governed by shallow traps and a long decay (∼350 μs) dominated by deep traps, creating an energy cascade that efficiently promotes radiative recombination while minimizing non-radiative losses. Our findings provide critical insights into defect-mediated, thermally-sensitive delayed emission mechanisms and establish [(CH3)3NPh]2MnBr4 as a lead-free, thermally stable material with high efficiency, making it an excellent candidate for next-generation optoelectronic applications, including solid-state lighting and temperature-sensitive devices.

Authors: Alanazi, M; Jana, A; Choi, WW; Taylor, RA; Yang, DC

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Applied Materials Today
• Volume: 44
• Article number: 102763
• Publication date: 2025-05-08
• Acceptance date: 2025-05-01
• DOI: 10.1016/j.apmt.2025.102763
• EISSN: 2352-9415
• ISSN: 2352-9407
• Language: English
• Keywords: lead-free optoelectronic materials; quantum yield; hybrid perovskites; defect-mediated luminescence; thermally activated delayed fluorescence; shallow and deep traps