Theoretical design of phosphorescence parameters for organic electro-luminescence devices based on iridium complexes
2009 (English)In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 358, no 3, 245-257 p.Article in journal (Refereed) Published
Tithe-dependent density functional theory with quadratic response methodology is used in order to calculate and compare spin-orbit coupling effects and the main mechanism of phosphorescence of the neutral Ir(ppy)(3) and cationic [Ir(bpy)(3)](3+) tris-iridium compounds, [Ir(ppy)(2)(bpy)](+) and [Ir(2-phenylpyridine)(2)(4,4'-tert-butyl-2,2'-bipyridine](+) complexes, including also the recently synthesised [Ir(2-phenylpyridine)(2)(4,4'-dimethylamino-2,2'-bipyridine](+) and [Ir(2,4-difluorophenylpyridine)(2)(4,4'-dimethylamino-2,2'-bipyridine](+) dyes, where ppy = 2-phenylpyridine and bpy = 2,2'-bipyridine ligands. Comparison with the symmetric, lighter and more studied [Ru(bpy)(3)](2+) and [Rh(bpy)(3)](3+) complexes is also resented. Variations in lifetimes for Ir(ppy)(3) and [Ir(bpy)(3)](3+) dyes as well as for the mixed cationic complexes are well reproduced by the quadratic response method. All the ortho-metalated iridium compounds exhibit strong phosphorescence, which is used in organic light-emitting diodes (OLEDs) to overcome the efficiency limit imposed by the formation of triplet excitons. The results from the first principle theoretical analysis of phosphorescence have helped to clarify the connections between the main features of electronic structure and the photo-physical properties of the studied heavy organometallic OLED materials.
Place, publisher, year, edition, pages
2009. Vol. 358, no 3, 245-257 p.
Time-dependent density functional theory, Quadratic response, Organic light emitting diodes, Phosphorescence
IdentifiersURN: urn:nbn:se:kth:diva-32514DOI: 10.1016/j.chemphys.2009.02.014ISI: 000265772000009ScopusID: 2-s2.0-63449116074OAI: oai:DiVA.org:kth-32514DiVA: diva2:410943
QC 201104152011-04-152011-04-152011-04-15Bibliographically approved