These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Phosphorescent iridium(III) complexes with nonconjugated cyclometalated ligands.
    Author: Song YH, Chiu YC, Chi Y, Cheng YM, Lai CH, Chou PT, Wong KT, Tsai MH, Wu CC.
    Journal: Chemistry; 2008; 14(18):5423-34. PubMed ID: 18425742.
    Abstract:
    A series of blue phosphorescent iridium(III) complexes 1-4 with nonconjugated N-benzylpyrazole ligands were synthesized and their structural, electrochemical, and photophysical properties were investigated. Complexes 1-4 exhibit phosphorescence with yields of 5-45 % in degassed CH2Cl2. Of the compounds, 1 showed emission that was nearly true blue at 460 nm with a lack of vibronic progression. These photophysical data clearly demonstrate that the methylene spacer of the cyclometalated N-benzylpyrazole chelate effectively interrupts the pi conjugation upon reacting with a third L X chelating chromophore. This gives a feasible synthesis for the blue phosphorescent complexes with a sufficiently large energy gap. In another approach, these complexes were investigated for their suitability for the host material in phosphorescent OLEDs. The device was synthesized by using 1 as the host for the green-emitting [Ir(ppy)3] dopant, which exhibits an external quantum conversion efficiency (EQE) of up to 11.4 % photons per electron (and 36.6 cdA(-1)), with 1931 Commission Internationale de L'Eclairage (CIE) coordinates of (0.30, 0.59), a peak power efficiency of 21.7 lmW(-1), and a maximum brightness of 32000 cdm(-2) at 14.5 V. At the practical brightness of 100 cdm(-2), the efficiency remains above 11 % and 18 lmW(-1), demonstrating its great potential as the host material for phosphorescent organic light-emitting diodes.
    [Abstract] [Full Text] [Related] [New Search]