A Combined Experimental and Computational Study on the Broadening Mechanism of the Luminescence in Narrow-Band Eu²⁺-Doped Phosphors

The Journal of Physical Chemistry C, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

In this work, we present a comprehensive study of the luminescence relaxation mechanism and associated spectral broadening in series Eu2+-doped narrow-band phosphors. It is highlighted that commonly used full-width at half-maximum (fwhm) no longer sensitive measure for quantifying emission bandwidth these materials. A thorough understanding factors contributing to narrow requires an explicit treatment magnetic structure ground emissive excited state manifolds. This incorporating spin–orbit coupling effects using wave function-based methods such as complete active space self-consistent field combined with second-order N-electron valence perturbation theory (CASSCF/NEVPT2). addition, dynamics calculations, one needs consider vibronic interactions on basis Franck–Condon (FC), Herzberg–Teller (HT), and, when necessary, pseudo Jahn–Teller (PJT) effects. Our analysis underscores controlling synergistic roles "static" "dynamic" are essential accurately assessing band systems. We show results can, principle, be generalized arbitrary set phosphor candidates can potentially aid experimental efforts toward developing novel phosphors enhanced luminescent properties.

Language: Английский

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Unraveling the Mechanism of Circularly Polarized Thermally Activated Delayed Fluorescence (CP-TADF) in Chiral Two-Coordinated Cu(I) Emitters: A Comprehensive Theoretical Exploration

Inorganic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: March 21, 2025

The circularly polarized thermally activated delayed fluorescence (CP-TADF) processes of four pairs Cu(I)-based chiral enantiomers were calculated by employing the path integral approach to dynamics. results reveal that introduction different substituents at various positions on planar CzP units significantly impacts dissymmetry factor gCPL CP luminescence (CPL). Substituting sixth position hydrogen unit with -CN or -Cl groups increases 2.1 × 10-3 and 2.2 in Sp-MAC-Cu-CNCzP-1 Sp-MAC-Cu-ClCzP, respectively. This is due a small electric transition dipole moment |μ| relatively large magnetic |m|. from CT excitation spatially separated highest-occupied molecular orbital (HOMO) lowest-unoccupied (LUMO) transitions S1 state, leading ΔE(S1 - T1) more efficient TADF. Interestingly, seventh-substituted MAC-Cu-CNCzP-2 complex exhibits substantial increase 0.346 eV, which consequently leads significant decrease kRISC rate, down 3.32 103 s-1, indicating further reverse intersystem crossing (RISC) are failed. Thus, design CP-TADF molecules, key lies regulating balancing factors affecting both TADF CPL properties.

Language: Английский

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Investigating the Mechanism of Thermally Activated Delayed Fluorescence Induced by Different Conformations of a Two-Coordinate Copper(I) Complex

The Journal of Physical Chemistry A, Journal Year: 2025, Volume and Issue: unknown

Published: June 4, 2025

The investigation of thermally activated delayed fluorescence (TADF) in carbene-metal-amide (CMA) complexes reveals that structurally flexible ligands can demonstrate significant TADF characteristics. A series four conformationally copper(I) featuring cyclic alkyl amino carbene (CAAC) and 10H-phenothiazine-5,5-dioxide (Ptz) were systematically studied using quantum chemical calculations. study examines the impact two key structural parameters, namely torsion angle φ (CAAC-Cu(I)-Ptz-1: perpendicular; CAAC-Cu(I)-Ptz-2 CAAC-Cu(I)-Ptz-3: coplanar; CAAC-Cu(I)-Ptz-4: anticoplanar) tilt β (near-planar arrangement: CAAC-Cu(I)-Ptz-3 > CAAC-Cu(I)-Ptz-2), on photophysical properties conformations. Geometrical excited-state analyses indicate CAAC-Cu(I)-Ptz-1, CAAC-Cu(I)-Ptz-2, CAAC-Cu(I)-Ptz-4 conformations are observed to have similar transitions, but their angles critically influence energy gap variations. Specifically, differences between excited states 0.10 0.20 eV, respectively, due distinct spans. Notably, increased diminishes contribution Cu, with lowest triplet state (T1) displaying 47% ligand-to-ligand charge transfer (LLCT) 28% metal-to-ligand (MLCT) character. combined minimum crossing point (MECP) spin-orbit coupling (SOC) elucidate effect reverse intersystem (RISC) rates: (0.41 eV MECP barrier) CAAC-Cu(I)-Ptz-1 (SOC = 4.35 cm-1) confirmed suppress RISC rates (1.09 × 104 1.09 108 s-1, respectively), while enhanced achieved through reduced barriers strengthened SOC interactions by (1.68 109 3.87 respectively). These findings highlight vital role ligand flexibility CMA emitters, offering valuable guidance for designing efficient materials.

Language: Английский

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Chiral Organometallic Complexes Derived from Helicenic N-Heterocyclic Carbenes (NHCs): Design, Structural Diversity, and Chiroptical and Photophysical Properties

Accounts of Chemical Research, Journal Year: 2024, Volume and Issue: 57(20), P. 2941 - 2952

Published: Oct. 3, 2024

ConspectusRecently, helicene derivatives have emerged as an important class of molecules with potential applications spanning over asymmetric catalysis, biological activity, magnetism, spin filtering, solar cells, and polymer science. To harness their full potential, especially emissive components in circularly polarized organic light-emitting diodes (CP-OLEDs), generating structural chemical diversity understanding the resulting photophysical chiroptical properties are crucial. In this Account, we shed light on engineering combining

Language: Английский

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Chiroptical activity of benzannulated N-heterocyclic carbene rhenium(i) tricarbonyl halide complexes: towards efficient circularly polarized luminescence emitters

Physical Chemistry Chemical Physics, Journal Year: 2023, Volume and Issue: 26(6), P. 4855 - 4869

Published: Nov. 14, 2023

The work describes the in-depth experimental and computational investigation of a novel series enantiomerically pure, circularly polarized emitters based on tris-carbonyl Re( i ) complexes.

Language: Английский

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