Energy migration within the 2E state of Cr3+
| Autor: | Mia Milos, Sebastien Rabaste, Selim Kairouani, Andreas Hauser |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Quenching (fluorescence)
Phonon Chemistry Resonant and phonon-assisted excitation energy migration Spectral diffusion Doping [Cr(ox)3]3 Chromophore Inorganic Chemistry Chemical physics Absorption band ddc:540 Materials Chemistry Physical and Theoretical Chemistry Atomic physics Ground state Luminescence Fluorescence line narrowing Excitation |
| Zdroj: | Coordination Chemistry Reviews, Vol. 252, No 23-24 (2008) pp. 2540-2551 |
| ISSN: | 0010-8545 |
| Popis: | Excitation energy migration is an important phenomenon at high concentration of luminescent chromophores. In crystalline solids it results in a quenching of the intrinsic luminescence of the chromophore as the excitation energy migrates to impurity centres or other forms of trap sites. As concluded from the extensively studied systems where Cr 3+ is doped as the active chromophore into inert host lattices, energy migration in crystalline solids is usually a phonon-assisted process, in which the simultaneous creation or annihilation of phonons helps to bridge the energy miss-match in the energy levels of two neighbouring chromophores within a inhomogeneously broadened absorption band. However, in the three-dimensional network systems [Ru(bpy) 3 ][NaCr(ox) 3 ] and [Rh(bpy) 3 ][NaCr(ox) 3 ]ClO 4 , it proved possible to unambiguously identify three different mechanisms for energy migration within the R 1 line of the 4 A 2 → 2 E transition of Cr 3+ . In addition to the common temperature dependant phonon-assisted process, a resonant process between the zero-field split components of the 4 A 2 ground state leading to a multi-line pattern in a fluorescence line narrowing spectrum and a quasi-resonant process within the same component leading to fast spectral diffusion can be identified at very low temperature. The parameters governing these processes are discussed and the behaviour of the model systems is compared to more conventional doped oxides and related systems. |
| Databáze: | OpenAIRE |
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