Photophysical and DFT investigation of imidazole-based hole transporting materials for phosphorescent OLEDs with high current efficiency

Sree, Vijaya Gopalan; Bathula, Chinna; Youi, Hae-Kyung; Sohn, Jung Inn; Im, Hyunsik

doi:10.1016/j.molliq.2021.116708

Cited by 13 publications

(7 citation statements)

References 32 publications

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“…The molecular structure stability was defined based on the positive frequency (cm −1 ) and the total energy (a.u.) at the unit level of b3pw91/6-31G*, according to the density functional theory (DFT), calculated using the GAUSSVIEW 5.0 software (Gaussian Inc., Wallingford, CT, USA) [69][70][71]. In this software, the GIF format molecules were loaded, optimized, and finally output the result files.…”

Section: Evaluation Of the Environment-friendliness And Functional Properties Of The Qns Derivatives-epi Gaussian Pharmacodynamics And Hqmentioning

confidence: 99%

Strategies to Control Human Health Risks Arising from Antibiotics in the Environment: Molecular Modification of QNs for Enhanced Plant–Microbial Synergistic Degradation

Sun

Zhao

2021

IJERPH

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In the present work, a comprehensive screening and evaluation system was established to improve the plant–microbial synergistic degradation effects of QNs. The study included the construction of a 3D-QSAR model, the molecular modification, environmental friendliness and functional evaluation of drugs, degradation pathway simulation, and human health risk assessment. Molecular dynamics was applied to quantify the binding capacity of QNs toward the plant degradation enzyme (peroxidase) and microbial degradation enzymes (manganese peroxidase, lignin peroxidase, and laccase). The fuzzy comprehensive evaluation method was used in combination with the weighted average method for normalization and assigning equal weights to the plant and microbial degradation effect values of the QNs. Considering the synergistic degradation effect value as the dependent variable and the molecular information of the QNs as the independent variable, a 3D-QSAR model was constructed for the plant–microbial synergistic degradation effect of QNs. The constructed model was then employed to conduct the molecular modification, environmental friendliness and functional evaluation, degradation pathway simulation, and human health risk assessment of transformation products using pharmacokinetics and toxicokinetics. The results revealed that the synergistic degradation effect 3D-QSAR (CoMSIA) model exhibited good internal and external prediction ability, fitting ability, stability, and no overfitting phenomenon. Norfloxacin (NOR) was used as the target molecule in the molecular modification. A total of 35 NOR derivatives with enhanced plant–microbial synergistic degradation effect (1.32–21.51%) were designed by introducing small-volume, strongly electronegative, and hydrophobic hydrogen bond receptor groups into the active group of the norfloxacin structure. The environment-friendliness and the functionality of NOR were evaluated prior to and after the modification, which revealed seven environment-friendly FQs derivatives exhibiting moderate improvement in stability and bactericidal efficacy. The simulation of the NOR plant and microbial degradation pathways prior to and after the modification and the calculation of the reaction energy barrier revealed Pathway A (D-17 to D-17-2) and Pathway B (D-17 to D-17-4) as the most prone degradation pathways in plants and Pathway A (D-17 to D-17-1) and Pathway B (D-17 to D-17-4) as the most prone degradation pathways in microorganisms. This demonstrated that the degradation of the modified NOR derivatives was significantly enhanced, with the hydroxylation and piperazine ring substitution reaction playing an important role in the degradation process. Finally, the parameters, including hepatotoxicity, mutagenicity, and rodent carcinogenicity, among others, predicted using the pharmacokinetics and toxicokinetics analyses revealed a significant reduction in the human health risk associated with the modified NOR, along with a considerable reduction in the toxicity of its transformation products, implying that the human health risk associated with the transformation products was reduced remarkably. The present study provides a theoretical basis for novel ideas and evaluation programs for improving the plant–microbial synergistic degradation of the QNs antibiotics for source control and drug design, thereby reducing the residues of these antibiotics and the associated hazard in the complex plant–soil environment, ultimately decreasing the potential risks to human health.

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Section: Evaluation Of the Environment-friendliness And Functional Properties Of The Qns Derivatives-epi Gaussian Pharmacodynamics And Hqmentioning

confidence: 99%

Strategies to Control Human Health Risks Arising from Antibiotics in the Environment: Molecular Modification of QNs for Enhanced Plant–Microbial Synergistic Degradation

Sun

Zhao

2021

IJERPH

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“…Moreover, one of the nitrogens of the heterocycle is electron-deficient similar to pyridine, whereas the other nitrogen is electron-rich similar to pyrrole . Therefore, substitution at the ring terminals with electron-donating and -accepting moieties may lead to the development of imidazole derivatives with interesting optical and electrical properties. , Hence, imidazole-based molecular or macromolecular systems have been widely explored as materials of choice for different layers of OLEDs that include electron transport materials (ETMs), hole-transport materials (HTMs), hosts, and emitters …”

Section: Introductionmentioning

confidence: 99%

“…Diphenyl phosphine oxide and benzimidazole derivatives have been developed as efficient ETMs for OLED application. , Similarly, phenanthroimidazole has been explored by several research groups for developing ultraviolet, deep-blue, green, and orange-red emitters. ,− Moreover, the imidazole functionality has also been used for developing host materials for OLEDs for wide-ranging emitters, starting from blue to green to red emitters. Indeed, the imidazole-based hosts have resulted in OLEDs with improved performance. ,− In addition, imidazole-based molecular materials have been investigated for their application as HTMs in OLEDs, although the imidazole-based HTMs have been more widely used in solar cells. ,, Together, imidazoles or fused-imidazoles have been one of the most remarkable heterocyclic cores for developing a wide spectrum of organic materials for optoelectronics applications.…”

Section: Introductionmentioning

confidence: 99%

Sterically Crowded Donor-Rich Imidazole Systems as Hole Transport Materials for Solution-Processed OLEDs

Kumar,

Sharma,

Thakur

et al. 2024

Langmuir

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Imidazole, being an interesting dinitrogenic five-membered heterocyclic core, has been widely explored during the last several decades for developing various fascinating materials. Among the different domains where imidazole-based materials find wide applications, the area of optoelectronics has seen an overwhelming growth of functional imidazole derivatives developed through remarkable design and synthesis strategies. The present work reports a design approach for integrating bulky donor units at the four terminals of an imidazole core, leading to the development of sterically populated imidazole-based molecular platforms with interesting structural features. Rationally chosen starting substrates led to the incorporation of a bulky donor at the four terminals of the imidazole core. In addition, homo-and cofunctional molecular systems were synthesized through a suitable combination of initial ingredients. Our approach was extended to develop a series of four molecular systems, i.e., Cz3PhI, Cz4I, Cz3PzI, and TPA3CzI, containing carbazole, phenothiazine, and triphenylamine as known efficient donors at the periphery. Given their interesting structural features, three sterically crowded molecules (Cz4I, Cz3PzI, and TPA3CzI) were screened by using DFT and TD-DFT calculations to investigate their potential as hole transport materials (HTMs) for optoelectronic devices. The theoretical studies on several aspects including hole reorganization and exciton binding energies, ionization potential, etc., revealed their potential as possible candidates for the hole transport layer of OLEDs. Single-crystal analysis of Cz3PhI and Cz3PzI established interesting structural features including twisted geometries, which may help attain high triplet energy. Finally, the importance of theoretical predictions was established by fabricating two solution-process green phosphorescent OLED devices using TPA3CzI and Cz3PzI as HTMs. The fabricated devices exhibited good EQE/PE and CE of ∼15%/56 lm/W/ 58 cd/A and ∼13%/47 lm/W/50 cd/A, respectively, at 100 cd/m 2 .

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“…Furthermore, Du et al and Park et al reported triphenylamine-based HTMs with PE of 78.7 and 38.5 lm/W, respectively. , Recently, Sun et al and Pan et al used crosslinked hole-transport materials and achieved EQEs of 8.9 and 15.4%, respectively. , Apart from that, Wang et al synthesized xanthene-based highly efficient hole-transport materials with PE and EQE of 94.2 lm/W and 24.7%, respectively, in green phosphorescent OLEDs . However, very few reports are available where arylamine and its derivatives have been used as HTMs in solution-processed devices. − High-triplet-energy HTMs are very crucial to obtain better device efficiency because they block the triplet excitons from EML and reduce exciton loss at the juncture of the HIL/EML. In the past, several acceptor units have been used in the construction of charge-transporting and emitting materials for OLED devices. − The proper combination of these acceptor units with electron donors leads to a twisted structure that helps boost the triplet energy and thermal stability of the developed material.…”

Section: Introductionmentioning

confidence: 99%

Computational Evaluation with Experimental Validation: Arylamine-Based Functional Hole-Transport Materials for Energy-Efficient Solution-Processed OLEDs

Kumar,

Kesavan,

Kumar

et al. 2023

J. Phys. Chem. C

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Ultra-efficient and stable OLED devices can be obtained via effective charge injection, accumulation, and exciton confinement into the emissive layer. However, the leakage of charge and excitons from the EML to adjacent layers can lead to low device performance. Thus, high-triplet-energy charge-transport materials (CTMs) are required to confront these issues. Herein, we demonstrate a class of efficient arylamine derivatives, viz. TPA-Py, TPA-2Py, and DPA-2Py, which were synthesized through the insertion of triphenyl pyridine as an acceptor unit to the aryl amino system to accomplish high triplet energy, thermal stability, and charge transportability during device operation. The charge-transfer analysis of the developed materials was accomplished for the S1 and T1 states through theoretical simulation. The intramolecular hole reorganization energies helped in understanding the hole transportability of these molecules. Single-crystal analysis indicated a considerable dihedral angle across the units, quasiplanar geometries, and the nonexistence of π–π stacking in the solid state. These molecular materials exhibited good thermal stability, which improve the morphological stability of their thin films. All of the molecules possess suitable HOMO energy levels for hole injection and appropriate LUMO energy levels for electron blocking from the emissive layer. Moreover, their high triplet energy (up to 2.69 eV) prevents exciton transfer from the EML to HTL and results in better device performance. The device with DPA-2Py as an HTM in a green OLED showed the maximum current efficiency (CE) and power efficiency (PE) values of ∼74 cd/A and ∼72 lm/W, respectively, with a maximum EQE of ∼21%. The PE of the current device is at par with the highest reported PE so far in solution-processed phosphorescent OLEDs.

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Photophysical and DFT investigation of imidazole-based hole transporting materials for phosphorescent OLEDs with high current efficiency

Cited by 13 publications

References 32 publications

Strategies to Control Human Health Risks Arising from Antibiotics in the Environment: Molecular Modification of QNs for Enhanced Plant–Microbial Synergistic Degradation

Strategies to Control Human Health Risks Arising from Antibiotics in the Environment: Molecular Modification of QNs for Enhanced Plant–Microbial Synergistic Degradation

Sterically Crowded Donor-Rich Imidazole Systems as Hole Transport Materials for Solution-Processed OLEDs

Computational Evaluation with Experimental Validation: Arylamine-Based Functional Hole-Transport Materials for Energy-Efficient Solution-Processed OLEDs

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