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RESEARCH PRODUCT
Self-trapped exciton in Li2GeO3
Maris SpingisAnatoly N. TrukhinUldis Rogulissubject
Range (particle radiation)ChemistryExcitonBiophysicsGeneral ChemistryCondensed Matter PhysicsBiochemistryAtomic and Molecular Physics and OpticsCrystalExcited stateUltrafast laser spectroscopyTriplet stateAtomic physicsAbsorption (electromagnetic radiation)Luminescencedescription
Abstract Self-trapped excitons (STE) are discovered in Li2GeO3 crystal. The PL band at 2.7 eV with a strong Stoke's shift is excited in the intrinsic absorption range of Li2GeO3 crystal, in which the optical gap is situated at 6 eV. The activation energy of the STE luminescence thermal quenching is not monoenergetic and is situated in the range 40–100 meV. The luminescence is strongly polarized. The decay kinetics can be characterized by τ = 0.9 ms at 45 K. At 5 K it can be approximated by fast (0.6 ms) and slow (4–2.5 ms) components. Decay kinetics is determined by triplet state of STE splits in zero magnetic field. Two different excited triplet states (centers) have the average ODMR parameters [D] = 6.3 GHz and [E] = 0.6 GHz. The transient absorption of STE shows two bands at 3.7 and 4.7 eV, similar to transient absorption of STE in GeO2 crystal with the structure of α-quartz.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1997-06-01 | Journal of Luminescence |