Photoluminescence characteristics of Ir(ppy)3 and PtOEP doped in TPD host material

Tsuboi, Taijū; Murayama, Hirokazu; Penzkofer, Alfons

doi:10.1016/j.tsf.2005.07.020

Cited by 35 publications

(30 citation statements)

References 10 publications

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“…The long lifetime causes the energy dissipation from the T 1 level in PtOEP. This is confirmed from the observation that the PtOEP emission intensity decreases with increasing temperature from 10 to 300 K [11], because the energy dissipation rate increases with increasing temperature as mentioned later.…”

Section: Phosphorescence Intensity Of Ptoepsupporting

confidence: 75%

Photophysics and electroluminescence of organometallic compounds with d-electrons

Tsuboi

Aljaroudi

2007

Journal of Alloys and Compounds

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Section: Phosphorescence Intensity Of Ptoepsupporting

confidence: 75%

Photophysics and electroluminescence of organometallic compounds with d-electrons

Tsuboi

Aljaroudi

2007

Journal of Alloys and Compounds

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“…The strong PIA signal of PtOEP MEH-PPV is around 1.27 eV, [ 22,23 ] which lies below the energy level of 1.9 eV [ 24 ] of the phosphorescent dye, PtOEP. The PL quenching of MEH-PPV thus occurs neither by singlet-singlet energy transfer [ 21 ] nor by exciton dissociation.…”

Section: Resultsmentioning

confidence: 87%

Triplet Exciton and Polaron Dynamics in Phosphorescent Dye Blended Polymer Photovoltaic Devices

Lee

Hwang

Byeon

et al. 2010

Adv Funct Materials

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The triplet exciton and polaron dynamics in phosphorescent dye (PtOEP) blended polymer (MEH‐PPV) photovoltaic devices are investigated by quasi‐steady‐state photo‐induced absorption (PIA) spectroscopy. According to the low‐temperature PIA and photoluminescence (PL) results, the increase in strength of the triplet‐triplet (T1‐Tn) absorption of MEH‐PPV in the blend system originates from the triplet‐triplet energy transfer from PtOEP to MEH‐PPV. The PtOEP blended MEH‐PPV/C60 bilayer photovoltaic device shows a roughly 30%–40% enhancement in photocurrent and power‐conversion efficiency compared to the device without PtOEP. However, in contrast to the bilayer device results, the bulk heterojunction photovoltaic devices do not show a noticeable change in photocurrent and power‐conversion efficiency in the presence of PtOEP. The PIA intensity, originating from the polaron state, is only slightly higher (within the experimental error), indicating that carrier generation in the bulk heterojunction is not enhanced in the presence of PtOEP. The rate and probability of the exciton dissociation between PtOEP and PCBM is much faster and higher than that of the triplet‐triplet energy transfer between PtOEP and MEH‐PPV.

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“…The same rate was assumed for the Dexter transfer between the host and guest molecules. The triplet energy levels-determining the exciton diffusion-were taken from experiment 14,18 and Gaussian excitonic energetic disorder of 0.1 eV was assumed. At least 124 possible neighbors were considered for each charge or exciton hop.…”

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confidence: 99%

Monte Carlo study of efficiency roll-off of phosphorescent organic light-emitting diodes: Evidence for dominant role of triplet-polaron quenching

Eersel

Bobbert

Janssen

et al. 2014

Applied Physics Letters

102

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We present an advanced molecular-scale organic light-emitting diode (OLED) model, integrating both electronic and excitonic processes. Using this model, we can reproduce the measured efficiency roll-off for prototypical phosphorescent OLED stacks based on the green dye tris[2-phenylpyridine]iridium (Ir(ppy)3) and the red dye octaethylporphine platinum (PtOEP) and study the cause of the roll-off as function of the current density. Both the voltage versus current density characteristics and roll-off agree well with experimental data. Surprisingly, the results of the simulations lead us to conclude that, contrary to what is often assumed, not triplet-triplet annihilation but triplet-polaron quenching is the dominant mechanism causing the roll-off under realistic operating conditions. Simulations for devices with an optimized recombination profile, achieved by carefully tuning the dye trap depth, show that it will be possible to fabricate OLEDs with a drastically reduced roll-off. It is envisaged that J90, the current density at which the efficiency is reduced to 90%, can be increased by almost one order of magnitude as compared to the experimental state-of-the-art.

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Photoluminescence characteristics of Ir(ppy)3 and PtOEP doped in TPD host material

Cited by 35 publications

References 10 publications

Photophysics and electroluminescence of organometallic compounds with d-electrons

Photophysics and electroluminescence of organometallic compounds with d-electrons

Triplet Exciton and Polaron Dynamics in Phosphorescent Dye Blended Polymer Photovoltaic Devices

Monte Carlo study of efficiency roll-off of phosphorescent organic light-emitting diodes: Evidence for dominant role of triplet-polaron quenching

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