Conjugated copolymers bearing 2,7-dithienylphenanthrene-9,10-dialkoxy units: highly soluble and stable deep-blue emissive materials

2020 ◽  
Vol 44 (22) ◽  
pp. 9557-9564
Author(s):  
Noorullah Baig ◽  
Suchetha Shetty ◽  
Sadiara Fall ◽  
Saleh Al-Mousawi ◽  
Thomas Heiser ◽  
...  
Keyword(s):  
High Stability ◽  
Blue Emission ◽  
Quantum Yields ◽  
Deep Blue ◽  
Conjugated Copolymers

Excellent yields, high stability and solubility. Mw = 36.5–152.0 kDa and Đ = 2.5–3.0. Deep-blue emission with quantum yields up to 17%.

Cu-catalysed direct C–H (hetero)arylation of [1,2,4]triazolo[4,3-a]pyridine to construct deep-blue-emitting luminophores

2015 ◽  
Vol 13 (19) ◽  
pp. 5372-5375 ◽  
Author(s):  
Jie Wu ◽  
Qiulin You ◽  
Jingbo Lan ◽  
Qiang Guo ◽  
Xiaoyu Li ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Blue Emission ◽  
Quantum Yields ◽  
High Quantum ◽  
Deep Blue

An efficient protocol for the synthesis of 3-aryl-[1,2,4]triazolo[4,3-a]pyridines has been developed via Cu-catalysed direct C–H (hetero)arylation. The resulting compounds exhibit deep-blue emission with high quantum yields, photostability, and thermal stability.

Synthesis and optical and electrochemical properties of water-soluble cationic fluorophores based on bispyridinium and dibenzothiophene-S,S-dioxide

2017 ◽  
Vol 41 (4) ◽  
pp. 1696-1703 ◽  
Author(s):  
Guiting Chen ◽  
Ruifeng He ◽  
Wei Yang ◽  
Bin Zhang
Keyword(s):  
Electrochemical Properties ◽  
Blue Emission ◽  
Water Soluble ◽  
Quantum Yields ◽  
Deep Blue

Two water-soluble cationic fluorophores (FSOPyCl and FSOmiCl) based on bispyridinium and dibenzothiophene-S,S-dioxide show deep blue emission, and exhibit high photoluminescence quantum yields of 69% and 50% in water, respectively.

scholarly journals Planar and Rigid Pyrazine Based TADF Emitter for Deep Blue Bright Organic Light Emitting Diodes

2021 ◽  
Author(s):  
P Rajamalli ◽  
Dongyang Chen ◽  
Subeesh Madayanad Suresh ◽  
Youichi Tsuchiya ◽  
Chihaya Adachi ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Coupling Efficiency ◽  
Blue Emission ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Triplet States ◽  
Light Emitting ◽  
Thermally Activated ◽  
Deep Blue ◽  
Show Temperature Dependence

<p>Two blue thermally activated delayed fluorescence (TADF) emitters bearing di-<i>tert</i>-butyl carbazoles as the electron donor groups and pyrazine (<b>DTCz-Pz</b>) or dipyrazine (<b>DTCz-Pz</b>) as the electron acceptor are presented. The DFT calculations predict <b>DTCz-Pz</b> and <b>DTCz-DPz</b> to possess high S<sub>1</sub> energies (3.19 eV and 3.08 eV, respectively), and relatively large E<sub>ST</sub> values (0.52 eV and 0.56 eV, respectively). The closely layered intermediate triplet states between S<sub>1</sub> and T<sub>1</sub>, predicted by DFT calculations, are expected to facilitate the reverse intersystem crossing (RISC) and improve spin-vibronic coupling efficiency between the excited states even the relatively larger ΔE<sub>ST</sub>s. The ΔE<sub>ST</sub>s for <b>DTCz-Pz</b> and <b>DTCz-DPz</b> are 0.27 eV and 0.38 eV, and both molecules show high photoluminescence quantum yields (65%, and 70%, respectively) and the decay lifetimes show temperature dependence in a PPT host, which is consistent that both molecules are TADF emitters in PPT. The OLEDs based on <b>DTCz-Pz</b> exhibit deep blue emission with λ<sub>EL</sub> of 460 nm and CIE of (0.15, 0.16). The maximum external quantum efficiency (EQE<sub>max</sub>) reaches 11.6%, with a maximum luminance (L<sub>max</sub>) of up to 6892 cd m<sup>-2</sup>, while the device based on <b>DTCz-DPz</b> exhibits sky blue emission with λ<sub>EL</sub> of 484 nm and CIE of (0.15, 0.30), an EQE<sub>max</sub> of 7.2%, and L<sub>max</sub> of 8802 cd m<sup>-2</sup>.</p>

scholarly journals Design of highly efficient deep-blue organic afterglow through guest sensitization and matrices rigidification

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Shen Xu ◽  
Wu Wang ◽  
Hui Li ◽  
Jingyu Zhang ◽  
Runfeng Chen ◽  
...  
Keyword(s):  
High Performance ◽  
Blue Emission ◽  
High Energy ◽  
Quantum Yields ◽  
Stimuli Responsive ◽  
Responsive Materials ◽  
Organic Optoelectronics ◽  
Deep Blue ◽  
Formidable Challenge ◽  
High Efficient

Abstract Blue/deep-blue emission is crucial for organic optoelectronics but remains a formidable challenge in organic afterglow due to the difficulties in populating and stabilizing the high-energy triplet excited states. Here, a facile strategy to realize the efficient deep-blue organic afterglow is proposed via host molecules to sensitize the triplet exciton population of guest and water implement to suppress the non-radiative decays by matrices rigidification. A series of highly luminescent deep-blue (405–428 nm) organic afterglow materials with lifetimes up to 1.67 s and quantum yields of 46.1% are developed. With these high-performance water-responsive materials, lifetime-encrypted rewritable paper has been constructed for water-jet printing of high-resolution anti-counterfeiting patterns that can retain for a long time (>1 month) and be erased by dimethyl sulfoxide vapor in 15 min with high reversibility for many write/erase cycles. These results provide a foundation for the design of high-efficient blue/deep-blue organic afterglow and stimuli-responsive materials with remarkable applications.

scholarly journals Planar and Rigid Pyrazine Based TADF Emitter for Deep Blue Bright Organic Light Emitting Diodes

2021 ◽  
Author(s):  
P Rajamalli ◽  
Dongyang Chen ◽  
Subeesh Madayanad Suresh ◽  
Youichi Tsuchiya ◽  
Chihaya Adachi ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Coupling Efficiency ◽  
Blue Emission ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Triplet States ◽  
Light Emitting ◽  
Thermally Activated ◽  
Deep Blue ◽  
Show Temperature Dependence

<p>Two blue thermally activated delayed fluorescence (TADF) emitters bearing di-<i>tert</i>-butyl carbazoles as the electron donor groups and pyrazine (<b>DTCz-Pz</b>) or dipyrazine (<b>DTCz-Pz</b>) as the electron acceptor are presented. The DFT calculations predict <b>DTCz-Pz</b> and <b>DTCz-DPz</b> to possess high S<sub>1</sub> energies (3.19 eV and 3.08 eV, respectively), and relatively large E<sub>ST</sub> values (0.52 eV and 0.56 eV, respectively). The closely layered intermediate triplet states between S<sub>1</sub> and T<sub>1</sub>, predicted by DFT calculations, are expected to facilitate the reverse intersystem crossing (RISC) and improve spin-vibronic coupling efficiency between the excited states even the relatively larger ΔE<sub>ST</sub>s. The ΔE<sub>ST</sub>s for <b>DTCz-Pz</b> and <b>DTCz-DPz</b> are 0.27 eV and 0.38 eV, and both molecules show high photoluminescence quantum yields (65%, and 70%, respectively) and the decay lifetimes show temperature dependence in a PPT host, which is consistent that both molecules are TADF emitters in PPT. The OLEDs based on <b>DTCz-Pz</b> exhibit deep blue emission with λ<sub>EL</sub> of 460 nm and CIE of (0.15, 0.16). The maximum external quantum efficiency (EQE<sub>max</sub>) reaches 11.6%, with a maximum luminance (L<sub>max</sub>) of up to 6892 cd m<sup>-2</sup>, while the device based on <b>DTCz-DPz</b> exhibits sky blue emission with λ<sub>EL</sub> of 484 nm and CIE of (0.15, 0.30), an EQE<sub>max</sub> of 7.2%, and L<sub>max</sub> of 8802 cd m<sup>-2</sup>.</p>

scholarly journals Naphthalonitriles featuring efficient emission in solution and in the solid state

2020 ◽  
Vol 16 ◽  
pp. 2960-2970
Author(s):  
Sidharth Thulaseedharan Nair Sailaja ◽  
Iván Maisuls ◽  
Jutta Kösters ◽  
Alexander Hepp ◽  
Andreas Faust ◽  
...  
Keyword(s):  
Excited State ◽  
Photophysical Properties ◽  
Aqueous Media ◽  
Blue Emission ◽  
Blue Shift ◽  
Red Shift ◽  
Quantum Yields ◽  
Structure Property ◽  
Time Resolved ◽  
Deep Blue

In this work, a series of γ-substituted diphenylnaphthalonitriles were synthesized and characterized. They show efficient emission in solution and in the aggregated state and their environment responsiveness is based on having variable substituents at the para-position of the two phenyl moieties. The excited state properties were fully investigated in tetrahydrofuran (THF) solutions and in THF/H2O mixtures. The size of the aggregates in aqueous media were measured by dynamic light scattering (DLS). The steady-state and time-resolved photoluminescence spectroscopy studies revealed that all the molecules show intense fluorescence both in solution and in the aggregated state. In THF solutions, a blue emission was observed for the unsubstituted (H), methyl- (Me) and tert-butyl- (t-Bu) substituted γ-diphenylnaphthalonitriles, which can be attributed to a weak π-donor capability of these groups. On the other hand, the methoxy- (OMe), methylsulfanyl- (SMe) and dimethylamino- (NMe2) substituted compounds exhibit a progressive red-shift in emission compared to H, Me and t-Bu due to a growing π-electron donating capability. Interestingly, upon aggregation in water-containing media, H, Me and t-Bu show a slight red-shift of the emission and a blue-shift is observed for OMe, SMe and NMe2. The crystal structure of Me allowed a detailed discussion of the structure–property relationship. Clearly, N-containing substituents such as NMe2 possess more electron-donating ability than the S-based moieties such as SMe. Moreover, it was found that NMe2 showed higher luminescence quantum yields (ΦF) in comparison to SMe, indicating that N-substituted groups could enhance the fluorescence intensity. Therefore, the π-donor nature of the substituents on the phenyl ring constitutes the main parameter that influences the photophysical properties, such as excited state lifetimes and photoluminescence quantum yields. Hence, a series of highly luminescent materials from deep blue to red emission depending on substitution and environment is reported with potential applications in sensing, bioimaging and optoelectronics.

scholarly journals Enhanced Crystallinity and Luminescence Characteristics of Hexagonal Boron Nitride Doped with Cerium Ions According to Tempering Temperatures

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 193
Author(s):  
Jae Yong Jung ◽  
Juna Kim ◽  
Yang Do Kim ◽  
Young-Kuk Kim ◽  
Hee-Ryoung Cha ◽  
...  
Keyword(s):  
Rare Earth ◽  
Boron Nitride ◽  
Uv Light ◽  
Hexagonal Boron Nitride ◽  
Heating Temperature ◽  
Blue Emission ◽  
Deep Blue ◽  
Cerium Ion ◽  
Luminescence Characteristics ◽  
Enhanced Crystallinity

Hexagonal boron nitride was synthesized by pyrolysis using boric acid and melamine. At this time, to impart luminescence, rare earth cerium ions were added to synthesize hexagonal boron nitride nanophosphor particles exhibiting deep blue emission. To investigate the changes in crystallinity and luminescence according to the re-heating temperature, samples which had been subjected to pyrolysis at 900 °C were subjected to re-heating from 1100 °C to 1400 °C. Crystallinity and luminescence were enhanced according to changes in the reheating temperature. The synthesized cerium ion-doped hexagonal boron nitride nanoparticle phosphor was applied to the anti-counterfeiting field to prepare an ink that can only be identified under UV light.

Highly efficient deep-blue fluorescent OLEDs based on anthracene derivatives with a triplet–triplet annihilation mechanism

2021 ◽  
Author(s):  
Zilong Wu ◽  
Shaoxin Song ◽  
Xiangyu Zhu ◽  
Hao Chen ◽  
Jiajin Chi ◽  
...  
Keyword(s):  
Quantum Yields ◽  
Carbazole Derivatives ◽  
Highly Efficient ◽  
Deep Blue ◽  
Anthracene Derivatives ◽  
Triplet Triplet Annihilation

New deep-blue molecules compromised of tert-butyl modified anthracene, p-benzonitrile, and carbazole derivatives provide external quantum yields of 7.03% and 7.28% in non-doped and doped deep-blue OLEDs, respectively.

High performance full color OLEDs based on a class of molecules with dual carrier transport channels and small singlet–triplet splitting

2015 ◽  
Vol 51 (53) ◽  
pp. 10632-10635 ◽  
Author(s):  
Chenglong Li ◽  
Shipan Wang ◽  
Weiping Chen ◽  
Jinbei Wei ◽  
Guochun Yang ◽  
...  
Keyword(s):  
High Performance ◽  
Carrier Transport ◽  
Blue Emission ◽  
Deep Blue ◽  
Full Color ◽  
Triplet Splitting ◽  
Transport Channels

The strong deep blue emission, good ambipolar carrier transport and small singlet–triplet splitting characteristics allow PPI-PPITPA and PPI-PPIPCz as emitting materials and hosts to fabricate high performance full color OLEDs.

scholarly journals Efficient Exciplex-Based Deep-Blue Organic Light-Emitting Diodes Employing a Bis(4-fluorophenyl)amine-Substituted Heptazine Acceptor

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5568
Author(s):  
Jie Li ◽  
Heqi Gong ◽  
Jincheng Zhang ◽  
Hui Liu ◽  
Li Tao ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Blue Emission ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Deep Blue ◽  
Photoluminescence Quantum Yield ◽  
Organic Light ◽  
High Maximum ◽  
Exciplex Emission ◽  
Amine Groups

The realization of a deep-blue-emitting exciplex system is a herculean task in the field of organic light-emitting diodes (OLEDs) on account of a large red-shifted and broadened exciplex emission spectrum in comparison to those of the corresponding single compounds. Herein, 2,5,8-tris(di(4-fluorophenyl)amine)-1,3,4,6,7,9,9b-heptaazaphenalene (HAP-3FDPA) was designed as an electron acceptor by integrating three bis(4-fluorophenyl)amine groups into a heptazine core, while 1,3-di(9H-carbazol-9-yl)benzene (mCP) possessing two electron-donating carbazole moieties was chosen as the electron donor. Excitingly, the exciplex system of 8 wt% HAP-3FDPA:mCP exhibited deep-blue emission and a high photoluminescence quantum yield of 53.2%. More importantly, an OLED containing this exciplex system as an emitting layer showed deep-blue emission with Commission Internationale de l’Eclairage coordinates of (0.16, 0.12), a peak luminance of 15,148 cd m−2, and a rather high maximum external quantum efficiency of 10.2% along with a low roll-off. This study not only reports an efficient exciplex-based deep-blue emitter but also presents a feasible pathway to construct highly efficient deep-blue OLEDs based on exciplex systems.

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