A very low lasing threshold of DABNA derivatives with DFB structures

Mamada, Masashi; Maedera, Satoshi; Oda, Susumu; Nguyen, Thanh Ba; Nakanotani, Hajime; Hatakeyama, Takuji; Adachi, Chihaya

doi:10.1039/d2qm01040b

Cited by 8 publications

(11 citation statements)

References 49 publications

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“…This decay rate value is higher than that of the recently reported triplet exciton harvesting MR-TADF emitter for OSSL application (1.5 × 10 8 s −1 ). 27 ■ CONCLUSIONS…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Next, the OSSL characteristic was investigated using the DFB resonator with the grating period (Λ) determined by the Bragg condition m λ Bragg = 2 n eff Λ m , where m is the order of diffraction, λ Bragg is the Bragg wavelength, and n eff is the effective refractive index of the waveguide. , For the optical feedback, the second-order diffraction ( m = 2) was selected, and lasing light can be out-coupled to the surface normal direction using the first-order Bragg diffraction. The 269 nm periodicity of the silica DFB structure was selected to realize the second-order diffraction at around 457 nm under consideration of n eff ∼ 1.7. , We utilized the sol–gel processing of silica (SiO 2 ) and nanoimprint lithography to fabricate the DFB resonator structure on a quartz substrate.…”

Section: Resultsmentioning

confidence: 99%

“…In organic materials, a representative triplet harvesting emission mechanism includes phosphorescence, thermally activated delayed fluorescence (TADF), , triplet–triplet fusion (TTF), , and hybridized local and charge-transfer (HLCT) emission. − Phosphorescent materials are not suitable for organic laser application because of the low radiative decay rate of triplet excitons. Some TADF materials were studied as a gain medium for OSSL, , but they suffer from low radiative decay rate because of the slow triplet exciton upconversion process by reverse intersystem crossing. TTF materials may have the same issue because of the slow upconversion process by the triplet–triplet collision.…”

Section: Introductionmentioning

confidence: 99%

“…22−26 Phosphorescent materials are not suitable for organic laser application because of the low radiative decay rate of triplet excitons. Some TADF materials were studied as a gain medium for OSSL, 27,28 but they suffer from low radiative decay rate because of the slow triplet exciton upconversion process by reverse intersystem crossing. TTF materials may have the same issue because of the slow upconversion process by the triplet−triplet collision.…”

Section: ■ Introductionmentioning

confidence: 99%

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Hybridized Local and Charge-Transfer Excited-State Emitter for a Blue Organic Solid-State Laser

Jang

Jeon

Patel

et al. 2023

ACS Appl. Mater. Interfaces

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The use of triplet excitons harvesting and short exciton lifetime organic emitters is important to improve the exciton utilization in organic semiconductor laser diodes. In this study, a hybridized local and charge-transfer (HLCT)-type molecule, 11-(3-(10-(4-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)anthracen-9-yl)phenyl)-11H-benzofuro[3,2-b]carbazole (PhAnMBf), is used as an emitter for blue-emitting organic solid-state lasers (OSSLs). The short exciton lifetime and high photoluminescence quantum yield of the PhAnMBf emitter allowed the fabrication of an organic laser with an emission wavelength of 453 nm, a small full width at half-maximum of 1.2 nm, and a threshold of 105 nJ/pulse, corresponding to 44 μJ/cm2, on the distributed feedback substrate. The anthracene-based PhAnMBf material showed the potential of the HLCT emitter as an OSSL.

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“…This decay rate value is higher than that of the recently reported triplet exciton harvesting MR-TADF emitter for OSSL application (1.5 × 10 8 s −1 ). 27 ■ CONCLUSIONS…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Hybridized Local and Charge-Transfer Excited-State Emitter for a Blue Organic Solid-State Laser

Jang

Jeon

Patel

et al. 2023

ACS Appl. Mater. Interfaces

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“…In order to overcome this problem, a great deal of interest has been recently devoted to the elaboration of thermally activated delayed uorescence (TADF) emitters [11][12][13] because they can also realize 100% IQE without the use of noble metals, TADF emitters are thus thought as the third generation OLED materials. The ability to produce OLEDs that compete and sometimes outperform phosphorescence-based OLEDs by harvesting both singlet and triplet excitons for light emission justi es the interest in this novel family of materials that Adachi and coworkers [14,15] have intensively promoted since 2011. In TADF emitters the energy gap (DE ST ) between the rst singlet excited state (S1) and the rst triplet excited state (T1) is extremely small [14].…”

Section: Introductionmentioning

confidence: 99%

Quanto-chemical insight into the singlet-triplet energy gap of diazine-based TADF blue emitters for OLED devices

Zaitri

Mekelleche

2023

Preprint

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A series of molecules (1a-d, 2a-d, 3a-c) with donor-linker-acceptor-linker-donor (D-p-A-p-D) architecture type, having the dimethylacridine (DMA) as a strong electron-donor, a diazine as electron-accepting core and the phenyl as the π-linker, were theoretically studied as potential thermally activated delayed fluorescence (TADF) emitters in organic light-emitting diodes (OLEDs). The effect of the electron-accepting core (pyridazine, pyrimidine or pyrazine) with various linking positions of the phenyl bridge, on the energy gap between the lowest excited singlet and triplet states (ΔEST) of the modeled molecules is investigated using DFT and TD-DFT methods and the level B3LYP/6-31G(d,p) was selected to calculate their photophysical and optoelectronic properties. The present study revealed that i) the all designed molecules have strong exciton binding energies, ii) they emit light in the range 480-540 nm in toluene solvent from a charge transfer state, iii) they exhibit TADF properties because of their small energy gaps (ΔEST<0.3eV). Additionally, the obtained results also indicate that the singlet-triplet energy gap can be effectively fine-tuned by the simple modification of the linking position of the DMA units via the phenyl bridge. Moreover, the NPA analysis shows that the more electron-deficient diazine core induces smaller HOMO-LUMO overlap and smaller DEST energy gap. Finally, the molecules 1c, 2b, 2c and 3b, where the two phenyl bridges are linked at 4,5-, 4,6-, 2,3- and 2,5-positions, respectively of the pyrimidine core, with the lowest ΔEST values should be the more suitable for efficient reverse intersystem crossing (rISC) in the TADF molecules.

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Progress and Perspective toward Continuous‐Wave Organic Solid‐State Lasers

et al. 2023

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A continuous‐wave (CW) organic solid‐state laser is highly desirable for spectroscopy, sensing, and communications, but is a significant challenge in optoelectronics. The accumulation of long‐lived triplet excitons and relevant excited‐state absorptions, as well as singlet–triplet annihilation, are the main obstacles to CW lasing. Here, progress in singlet‐ and triplet‐state utilizations in organic gain media is reviewed to reveal the issues in working with triplets. Then, exciton behaviors that inhibit light oscillations during long excitation pulses are discussed. Further, recent advances in increasing organic lasing pulse widths from microseconds toward the indication of CW operation are summarized with respect to molecular designs, advanced resonator architectures, triplet scavenging, and potential triplet contribution strategies. Finally, future directions and perspectives are proposed for achieving stable CW organic lasers with significant triplet contribution.

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A very low lasing threshold of DABNA derivatives with DFB structures

Abstract: For elucidating the potential of light amplification properties of thermally activated delayed fluorescence materials (TADF), the distributed feedback (DFB) laser devices using DABNA derivatives having a multiple-resonance effect were fabricated....

Cited by 8 publications

References 49 publications

Hybridized Local and Charge-Transfer Excited-State Emitter for a Blue Organic Solid-State Laser

Hybridized Local and Charge-Transfer Excited-State Emitter for a Blue Organic Solid-State Laser

Quanto-chemical insight into the singlet-triplet energy gap of diazine-based TADF blue emitters for OLED devices

Progress and Perspective toward Continuous‐Wave Organic Solid‐State Lasers

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