Change search
ReferencesLink to record
Permanent link

Direct link
Time-dependent density functional calculations of phosphorescence parameters for fac-tris(2-phenylpyridine) iridium
KTH, School of Biotechnology (BIO), Theoretical Chemistry.
KTH, School of Biotechnology (BIO), Theoretical Chemistry.
echnische Fachhochschule Wildau, University of Applied Sciences.
KTH, School of Biotechnology (BIO), Theoretical Chemistry.ORCID iD: 0000-0002-1763-9383
2007 (English)In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 333, no 03-feb, 157-167 p.Article in journal (Refereed) Published
Abstract [en]

fac-Tris(2-phenylpyridine) iridium [fac-Ir(PPY)(3)] produces strong phosphorescence and has therefore been used as materials in organic light emitting diodes to overcome the efficiency limit imposed by the formation of triplet excitons. Accounting for this circumstance we present in this paper a theoretical study of phosphorescence in the Ir(PPY)(3) complex. The spin-orbit coupling effects and the radiative lifetime in the high temperature limit (T) are calculated by time-dependent density functional theory using quadratic response technology in order to elucidate the main mechanism of the phosphorescence. It is found that the orbital structure of the T, state has a localized character and that the T1 -> S0 transition is determined mostly by charge transfer from one of the ligands to the metal. At the vertical S-0-T-1 excitation the triplet state is highly delocalized among all three ligands and has a mixed pi pi* and metal-to-ligand charge transfer character. The intensity borrowing from the S-0 to S-5 transitions is mostly responsible for the strong phosphorescence emission from the x and y spin sublevels. Our results concord with the experimental data on temperature and magnetic field dependence of the phosphorescence kinetics. The calculated radiative lifetime in the high temperature limit agrees well with the measured decay times (2 mu s) accounting for negligible non-radiative quenching of the lowest triplet state.

Place, publisher, year, edition, pages
2007. Vol. 333, no 03-feb, 157-167 p.
Keyword [en]
Ir(ppy)(3), phosphorescence, OLED, DFT, molecular-orbital methods, effective nuclear charges, free-base porphin, ab-initio, conjugated polymers, exciton formation, state properties, basis-sets, complexes, emission
National Category
Analytical Chemistry
URN: urn:nbn:se:kth:diva-16589DOI: 10.1016/j.chemphys.2007.01.021ISI: 000246060500008ScopusID: 2-s2.0-33947228297OAI: diva2:334631
QC 20100525Available from: 2010-08-05 Created: 2010-08-05 Last updated: 2010-12-03Bibliographically approved
In thesis
1. Electronic characterization of molecules with application to organic light emitting diodes
Open this publication in new window or tab >>Electronic characterization of molecules with application to organic light emitting diodes
2007 (English)Licentiate thesis, comprehensive summary (Other scientific)
Abstract [en]

The presented thesis is devoted to the field of organic light emitting

diodes (OLEDs). Time-dependent Kohn-Sham density functional theory

(TDDFT) is applied in order to eludicate optical properties such as fluorescence and

phosphorescence for some of the most important materials. The accuracy of TDDFT

is evaluated with respect to the calculated absorption and emission spectra for

commonly used light emitting polymers. A continuation of this work is devoted to

Polyfluorene as this polymer has proven to be very promising. In this study the

chain length dependence of its singlet and triplet excited states is analyzed as well

as the excited state structures.

Understanding the phosphorescence mechanism of tris(2-phenylpyridine)Iridium is

of importance in order to interpret the high efficiency of OLEDs

containing these specimens. The mechanism is analyzed by calculating

the electric transition dipole moments by means of TDDFT using

quadratic response functions. As not only the optical properties are essential for

effective devices, electron transfer properties are addressed. The electron

transfer capability of the sulfur and nitrogen analogues of Oxadiazole

is evaluated through their internal reorganization energy.

Place, publisher, year, edition, pages
Stockholm: KTH, 2007. viii, 43 p.
OLED, DFT, Marcus theory, Response theory
National Category
Theoretical Chemistry
urn:nbn:se:kth:diva-4349 (URN)978-97-7178-623-4 (ISBN)
2007-04-20, FA32, Main Building, Roslagstullsbacken 21, Albanova, 13:00
QC 20101109Available from: 2007-05-04 Created: 2007-05-04 Last updated: 2010-12-03Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Jansson, EmilMinaev, BorisÅgren, Hans
By organisation
Theoretical Chemistry
In the same journal
Chemical Physics
Analytical Chemistry

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 48 hits
ReferencesLink to record
Permanent link

Direct link