Solution-processed organic light-emitting diodes with emission from a doublet exciton; using (2,4,6-trichlorophenyl)methyl as emitter

Neier, Eric; Ugarte, Renzo Arias; Rady, Nader; Venkatesan, Swaminathan; Hudnall, Todd W.; Zakhidov, Alex

doi:10.1016/j.orgel.2017.02.010

Cited by 31 publications

(25 citation statements)

References 26 publications

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“…If injection of the hole into the HOMO occurs before the electron into the SOMO, positively charged, singlet and triplet intermediates are expected (see Fig. 4b 30 and thereby provides some indirect evidence for the mechanism in Fig. 4b.…”

Section: -mentioning

confidence: 88%

Efficient radical-based light-emitting diodes with doublet emission

Evans

Dong

et al. 2018

Nature

555

525

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Section: -mentioning

confidence: 88%

Efficient radical-based light-emitting diodes with doublet emission

Evans

Dong

et al. 2018

Nature

555

525

View full text Add to dashboard Cite

“…[ 20–28 ] We note that such organic radicals are also gaining significant attention beyond the OLED area as they can prove useful in fields such as spintronics, imaging, and quantum information technologies. [ 29–38 ] Among the limited examples of luminescent radicals reported thus far, derivatives of the chlorinated triphenylmethyl radical, TTM (tris(2,4,6‐trichlorophenyl)methyl, see Figure ), represent a promising class of open‐shell emitters for OLEDs. [ 24,25,39–44 ] The first excited electronic state in these radicals is a spin‐doublet state (D 1 ), which has the same spin configuration as the ground state (D 0 ); such an electronic structure naturally offers the way to circumvent the triplet harvesting problem present in closed‐shell emitters.…”

Section: Introductionmentioning

confidence: 99%

Radiative and Nonradiative Recombinations in Organic Radical Emitters: The Effect of Guest–Host Interactions

Abroshan

Coropceanu

Brédas

2020

Adv Funct Materials

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Radical‐carrying organic molecules have received significant attention to bypass the issue related to harvesting triplet excitons in current light‐emitting materials. While the computational efforts conducted so far have treated these radical emitters as isolated entities, in actual devices, they are embedded in a host matrix and subject to emitter–host interactions. Here, by combining molecular dynamics simulations and density functional theory calculations, the impact of the host matrix on the optoelectronic performance of radical emitters is evaluated, taking as a representative example the (4‐ncarbazolyl‐2,6‐dichlorophenyl)bis(2,4,6‐trichlorophenyl)‐methyl (TTM‐3NCz) radical emitter dispersed in a 4,4‐bis(carbazol‐9‐yl)biphenyl (CBP) host. A morphological analysis shows that steric effects around the radical centers, carried by the TTM electron‐poor moieties of the emitters, disfavor π–π interactions with the host molecules, which leads to random intermolecular orientations around the TTM moieties. The 3NCz electron‐rich moieties of the emitters, however, have much lesser spatial hindrance for intermolecular π–π stacking, which modulates the structural and electronic properties of the emitters in the host matrix. The influence of dynamic and static disorders on the radiative and nonradiative recombination processes is also investigated and it is found that the rates of nonradiative recombination are small, which opens the way to 100% internal quantum efficiency for the doublet‐based emission process.

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“…Tr is(2,4,6-trichlorophenyl)methyl [26] and perchlorotriphenylmethyl [27] radicals (1 and 2 respectively in Figure 1) are two common persistent trityl derivatives which show photoluminescence. [28,29] In spite of some drawbacks concerning their photostability in solution, the preparation of organic light emitting diodes (OLEDs) with electroluminescent layers based on 1 [30,31] has been successfully achieved and, very recently,the highest value of external quantum efficiency for adeep-red and infrared OLED have been reported. [32] Several synthetic approaches have been pursued aiming to obtain higher photostability and luminescence quantum yield (LQY) or red-shifted emissions [33^39] for this organic radical, highlighting its great tailorability.F inally,t he influence of rigid environments on their luminescent properties have also been considered.…”

Section: Introductionmentioning

confidence: 99%

Organic Free Radicals as Circularly Polarized Luminescence Emitters

et al. 2019

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Chiroptical properties of two chiral atropisomers of propeller‐like trityl‐based radical derivatives have been analyzed. A new absolute configuration (AC) assignment has been made, according to the combination of experimental and theoretical data. In this sense, their ACs have been determined through the comparison of the Cotton effects recorded by electronic circular dichroism (ECD) with the theoretical ECD of the open shell structures obtained by TD‐DFT calculations. Finally, their circularly polarized luminescence (CPL) responses have been addressed. Remarkably, this is the first description of organic free radicals as intrinsic CPL emitters. Opposite signed CPL has been detected for each pair of conformers, with acceptable luminescent dissymmetry factors (|glum|≈0.5–0.8×10−3) considering their pure organic nature. In fact, highly efficient chiral emissions have been demonstrated, according to the comparison of |glum| with their respective absorption anisotropy factors (|gabs|). This pioneering study lays the foundations for the optimization of new magnetically active organic chiral emitters.

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Solution-processed organic light-emitting diodes with emission from a doublet exciton; using (2,4,6-trichlorophenyl)methyl as emitter

Cited by 31 publications

References 26 publications

Efficient radical-based light-emitting diodes with doublet emission

Efficient radical-based light-emitting diodes with doublet emission

Radiative and Nonradiative Recombinations in Organic Radical Emitters: The Effect of Guest–Host Interactions

Organic Free Radicals as Circularly Polarized Luminescence Emitters

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