1,4‐Bis(diarylamino)‐2,5‐bis(4‐cyanophenylethenyl)benzenes: Fluorophores Exhibiting Efficient Red and Near‐Infrared Emissions in Solid State

Shimizu, Masaki; Kaki, Rina; Takeda, Youhei; Hiyama, Tamejiro; Nagai, Naomi; Yamagishi, H.; Furutani, Hiroyuki

doi:10.1002/ange.201108943

Cited by 59 publications

(21 citation statements)

References 81 publications

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“…However, the top red TADF OLED is still below 20% EQE, let alone the deep‐red or near‐infrared (NIR) TADF OLEDs. The reason is that the emission wavelength tends to be negatively related to the luminescence efficiency of NIR fluorophores, which is in agreement with the energy gap law . This law makes the NIR TADF OLEDs very challenged in achieving high performance.…”

Section: Introductionsupporting

confidence: 54%

Efficient Near‐Infrared Emission by Adjusting the Guest–Host Interactions in Thermally Activated Delayed Fluorescence Organic Light‐Emitting Diodes

Yuan

Shi

et al. 2018

Adv Funct Materials

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Thermally activated delayed fluorescence materials can effectively achieve high efficiency by harvesting singlet and triplet excitons in organic lightemitting diodes (OLEDs). However, the choice of host material has a huge impact on the efficiency of the device, especially for the near-infrared (NIR) luminescent material. In this contribution, a series of host materials are used to match the thermally activated delayed fluorescence emitter, 3,4-bis(4-(diphenylamino)phenyl)acenaphtho[1,2-b]pyrazine-8,9-dicarbonitrile (APDC-DTPA), for fabricating NIR OLEDs. All the host materials have the higher triplet energy than that of APDC-DTPA. As the organometallic compound of Zn(BTZ) 2 has relatively stronger dipole moment, the electroluminescence spectral peak of doped device shows strong bathochromic shift exceeding 700 nm and changes with doping concentration. Finally, the extremely high external quantum efficiency of 7.8% (with 10 wt% of doping concentration) and 5.1% (with 20 wt% of doping concentration) are achieved with the emission peaks of 710 and 728 nm, respectively, which are superior to that of the device based on the other host materials. The approach is feasible to achieve bathochromic shift and highly efficient fluorescent OLEDs.

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Section: Introductionsupporting

confidence: 54%

Efficient Near‐Infrared Emission by Adjusting the Guest–Host Interactions in Thermally Activated Delayed Fluorescence Organic Light‐Emitting Diodes

Yuan

Shi

et al. 2018

Adv Funct Materials

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“…Moreover, dyes 2 a and 4 displayed the highest Φ f values (19.5 % at 722 nm and 15.5 % at 755 nm, respectively) reported to date for a solid‐state organic dye with fluorescence emission at a wavelength beyond 700 nm. Recently values of 6 % at 743 nm6f and 30 % at 702 nm7b were reported and represented to date the highest values found in literature.…”

Section: Resultsmentioning

confidence: 91%

Efficient NIR‐Light Emission from Solid‐State Complexes of Boron Difluoride with 2′‐Hydroxychalcone Derivatives

D’Aléo

Gachet

Heresanu

et al. 2012

Chemistry A European J

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This article describes a series of nine complexes of boron difluoride with 2'-hydroxychacone derivatives. These dyes were synthesized very simply and exhibited intense NIR emission in the solid state. Complexation with boron was shown to impart very strong donor-acceptor character into the excited state of these dyes, which further shifted their emission towards the NIR region (up to 855 nm for dye 5 b, which contained the strongly donating triphenylamine group). Strikingly, these optical features were obtained for crystalline solids, which are characterized by high molecular order and tight packing, two features that are conventionally believed to be detrimental to luminescence in organic crystals. Remarkably, the emission of light from the π-stacked molecules did not occur at the expense of the emission quantum yield. Indeed, in the case of pyrene-containing dye 4, for example, a fluorescence quantum yield of about 15 % with a fluorescence emission maximum at 755 nm were obtained in the solid state. Moreover, dye 3 a and acetonaphthone-based compounds 1 b, 2 b, and 3 b showed no evidence of degradation as solutions in CH(2) Cl(2) that contained EtOH. In particular, solutions of brightly fluorescent compound 3 a (brightness: ε×Φ(f) =45,000 M(-1) cm(-1)) could be stored for long periods without any detectable changes in its optical properties. All together, these new dyes possess a set of very interesting properties that make them promising solid-state NIR fluorophores for applications in materials science.

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“…[10] In a solid film, the fluorescence efficiency is further reduced because of the nonradiative process induced by dipole-dipole interactions of these polar chromophores. [11] Thus, for highly efficient NIR OLEDs, the D-A chromophores should possess a reasonable radiative-transition rate, and the fluorescence efficiency should be maintained as well as possible in the solid film. More importantly, further EQE improvement of fluorescent NIR OLEDs (FOLEDs) based on D-A chromophores requires an innovative molecular approach.…”

mentioning

confidence: 99%

“…To the best of our knowledge, the performance of the PTZ-BZP device places it among the best undoped NIR FOLEDs. [6,8,11] The theoretical value of the radiative exciton ratio was calculated by the following equation:…”

mentioning

confidence: 99%

Highly Efficient Near‐Infrared Organic Light‐Emitting Diode Based on a Butterfly‐Shaped Donor–Acceptor Chromophore with Strong Solid‐State Fluorescence and a Large Proportion of Radiative Excitons

et al. 2014

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The development of near-infrared (NIR) organic light-emitting diodes (OLEDs) is of growing interest. Donor-acceptor (D-A) chromophores have served as an important class of NIR materials for NIR OLED applications. However, the external quantum efficiencies (EQEs) of NIR OLEDs based on conventional D-A chromophores are typically below 1 %. Reported herein is a butterfly-shaped D-A compound, PTZ-BZP. A PTZ-BZP film displayed strong NIR fluorescence with an emission peak at 700 nm, and the corresponding quantum efficiency reached 16 %. Remarkably, the EQE of the NIR OLED based on PTZ-BZP was 1.54 %, and a low efficiency roll-off was observed, as well as a high radiative exciton ratio of 48 %, which breaks through the limit of 25 % in conventional fluorescent OLEDs. Experimental and theoretical investigations were carried out to understand the excited-state properties of PTZ-BZP.

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1,4‐Bis(diarylamino)‐2,5‐bis(4‐cyanophenylethenyl)benzenes: Fluorophores Exhibiting Efficient Red and Near‐Infrared Emissions in Solid State

Cited by 59 publications

References 81 publications

Efficient Near‐Infrared Emission by Adjusting the Guest–Host Interactions in Thermally Activated Delayed Fluorescence Organic Light‐Emitting Diodes

Efficient Near‐Infrared Emission by Adjusting the Guest–Host Interactions in Thermally Activated Delayed Fluorescence Organic Light‐Emitting Diodes

Efficient NIR‐Light Emission from Solid‐State Complexes of Boron Difluoride with 2′‐Hydroxychalcone Derivatives

Highly Efficient Near‐Infrared Organic Light‐Emitting Diode Based on a Butterfly‐Shaped Donor–Acceptor Chromophore with Strong Solid‐State Fluorescence and a Large Proportion of Radiative Excitons

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