Efficient organic light-emitting diodes with phosphorescent platinum complexes containing N∧C∧N-coordinating tridentate ligand

Sotoyama, Wataru; Satoh, Tasuku; Sawatari, Norio; Inoue, Hiroshi

doi:10.1063/1.1901826

Cited by 85 publications

(75 citation statements)

References 18 publications

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“…8,9 Additionally, owing to their propensity to form highly emissive bimolecular excimers or aggregates, they are of particular interest for the production of white OLEDs (WOLEDs). The combination of efficient triplet monomer and excimer emission to generate broad-band light across the visible spectrum has been put forward as an attractive route to single-dopant white-emitting devices.…”

Section: -7mentioning

confidence: 99%

Cyclometallated platinum(ii) complexes of 1,3-di(2-pyridyl)benzenes for solution-processable WOLEDs exploiting monomer and excimer phosphorescence

Mróz¹,

Botta²,

Giovanella³

et al. 2011

J. Mater. Chem.

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Two cyclometallated platinum(II) complexes, N^C^N-5-fluoro-1,3-di(2-pyridyl)benzene platinum(II) chloride, FPtCl, and N^C^N-5-methyl-1,3-di(2-pyridyl)benzene platinum(II) isothiocyanate, MePtNCS, have been synthesized and characterized. Both complexes are highly efficient phosphorescent green emitters which can also display excimer emission in the red region. They have been studied as triplet emitters in solution-processed, multilayer organic light-emitting diodes (OLEDs), together with the known complex of 5-methyl-1,3-di(2-pyridyl)benzene, MePtCl, for comparison. The trend in efficiencies of the OLEDs prepared correlates with the charge-trapping properties of the complexes. The most efficiently emitting complex, FPtCl, was used as the dopant in a solution-processed white OLED, employing monomer and excimer emission.

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Section: -7mentioning

confidence: 99%

Cyclometallated platinum(ii) complexes of 1,3-di(2-pyridyl)benzenes for solution-processable WOLEDs exploiting monomer and excimer phosphorescence

Mróz¹,

Botta²,

Giovanella³

et al. 2011

J. Mater. Chem.

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“…in the field of supramolecular chemistry, [45][46][47][48][49][50][51][52] or as chemosensors, [53][54][55][56][57][58][59] switches, 60-62 metallomesogens [63][64][65][66][67][68] and also due to their photoluminescent and electronic properties, [69][70][71][72][73][74][75][76][77][78][79][80][81][82][83] no attempts will be made to include these aspects, even when related to ''rollover'' cyclometalated complexes, because the ''rollover'' cyclometalated ligands in these systems mostly act as mere spectators. In this review, the focus will be rather on the ''rollover'' process itself.…”

Section: -42mentioning

confidence: 99%

“Rollover” cyclometalation – early history, recent developments, mechanistic insights and application aspects

2012

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''Rollover'' cyclometalation constitutes a special case among the well-known class of cyclometalation reactions. An overview is given that covers the very first description of this reaction type, as well as recent developments. In addition, not only condensed-phase experiments are reviewed, but also investigations based on mass spectrometric techniques, together with ''in silico'' studies using DFTbased calculations are considered. While the latter two methods allow for a detailed analysis of the intrinsic factors that affect the reaction mechanisms, consideration of all three regimes permits to develop a coherent mechanistic picture and to address the often noted gap between condensed-and gasphase studies. Moreover, the quite unexpected reactivity of ''rollover'' cyclometalated complexes in gasphase experiments, as well as potential applications, e.g. in synthetic procedures, are discussed in some detail.

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“…For the devices it was found that even at a high voltage the luminescence intensity is still quite low. Comparing the device performances of D7 and D8 with cyclometalated platinum(II) complexes bearing a 3,5-di(2-pyridyl)-4-tolyl ligand 58 and a 2,2′-bipyridyl-6-phenyl ligand 59 the performances of D7 and D8 are rather low. These should be optimized to become of interest for practical applications.…”

mentioning

confidence: 99%

Substituted 4,4′-Stilbenoid NCN-Pincer Platinum(II) Complexes. Luminescence and Tuning of the Electronic and NLO Properties and the Application in an OLED

et al. 2008

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A series of 4,4′-disubstituted organic-organometallic stilbenes, i.e., the 4′-substituted stilbenoid-NCN-pincer platinum(II) complexes [PtCl(NCN-R-4)] (NCN-R-4 ) [C 6 H 2 (CH 2 NMe 2 ) 2 -2,6-R-4] -in which R ) C 2 H 2 C 6 H 4 -R′-4′ with R′ ) NPh 2 , NMe 2 , OMe, SiMe 3 H, I, CN, NO 2 ) (1-8), were studied for their electronic, electrochemical, and NLO properties. Complex 7 was also chemically oxidized using Cu(II)Cl 2 , yielding the [Pt(IV)Cl 3 (NCN(C 2 H 2 C 6 H 4 -CN-4′)-4)] complex 11. In contrast to 1 and 7, 11 did not show luminescent properties in solution at room temperature. In the solid state (X-ray crystallography) 11 has an overall bent structure, with the pincer moiety and the cyano group beneath the plane of the central double bond. Stilbenoid pincer complex 1 (R′ ) NPh 2 ) was also studied with UV/vis spectroscopy in a series of different solvents. The compound shows an intense low-energy transition band, appearing at a lower energy (λ max ) 374-379 nm) than 2 (R′ ) NMe 2 ), which contains a stronger donor group. The UV/vis absorption data of a selected series of stilbenoid pincer platinum complexes were interpreted in terms of a qualitative orbital model based on DFT and TD-DFT calculations. The trends observed in the transition energies correlate well with the donor/acceptor properties of the substituents. It was shown that the HOMO-LUMO gap of the stilbenoid pincer platinum compounds decreases when going from an electron-neutral group (R′ ) H) toward an electron-donating (R′ ) NMe 2 ) or -accepting (R′ ) NO 2 ) group. The fluorescence properties of 1 were also investigated using fluorescence and laser spectroscopy, showing that the metal center favors nonradiative decay from the excited state to the ground state. For 7 (R′ ) CN), solid-state 13 C CP/MAS NMR measurements were performed, and a value of 1 J( 13 C, 195 Pt) ) 1003 ( 15 Hz was obtained for the C ipso carbon, reflecting π-contributions in the carbon-metal bond. The cyclic voltammetry study on the complexes revealed an irreversible oxidation from Pt(II) to Pt(IV). In general the oxidation potential is influenced by the electronic character of the R′ substituent. The influence of the para R′ substituent on the hyperpolarizability of the compound was investigated using the femtosecond (frequencyresolved) HRS technique. For 1-7 good zzz values were measured ( zzz ranging from (164-1324) × 10 -30 esu) with the highest value for 6 (R′ ) I). The higher zzz values were found for the compounds that contain a low-energy UV/vis absorption band and/or a large absorption coefficient. Donor-acceptor complexes 7 and 8 were successfully applied in an organic light-emitting diode (OLED). In the electroluminescence spectrum of 7 (R′ ) CN) a low-energy emission band was observed at 643 nm. This band also appeared in the solid-state luminescence spectra of 7, however, only at low temperatures (298-15 K). The emission band was assigned to result from a triplet excited state. The present study shows that the introduction of a NCN-pincer platinum fragment ...

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Efficient organic light-emitting diodes with phosphorescent platinum complexes containing N∧C∧N-coordinating tridentate ligand

Cited by 85 publications

References 18 publications

Cyclometallated platinum(ii) complexes of 1,3-di(2-pyridyl)benzenes for solution-processable WOLEDs exploiting monomer and excimer phosphorescence

Cyclometallated platinum(ii) complexes of 1,3-di(2-pyridyl)benzenes for solution-processable WOLEDs exploiting monomer and excimer phosphorescence

“Rollover” cyclometalation – early history, recent developments, mechanistic insights and application aspects

Substituted 4,4′-Stilbenoid NCN-Pincer Platinum(II) Complexes. Luminescence and Tuning of the Electronic and NLO Properties and the Application in an OLED

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