Electroluminescence Characteristics of a New Green-Emitting Phenylphenothiazine Derivative with Phenylbenzimidazole Substituent

Ahn, Yeonseon; Jang, Eun Hyang; Cha, Yong-Bum; Kim, Mansu; Ahn, Kwang‐Hyun; Kim, Young Chul

doi:10.5012/bkcs.2013.34.1.107

Cited by 14 publications

(7 citation statements)

References 18 publications

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“…10 −6 cm 2 V −1 s −1 ). These low mobility values are comparable to those reported in the literature for other solution-deposited3233343569 and thermally evaporated70 phenothiazine derivatives. To the best of our knowledge, the mobility of O-1 is the highest reported for phenothiazine-based small molecules, without complexation with iodine.…”

Section: Resultssupporting

confidence: 89%

“…Phenothiazines are good electron-donors in photo-excited charge transfer transitions, and display a low and reversible oxidation potential for the generation of a stable radical cation 16 17 18 19 20 21 . Their ability to suppress molecular aggregation due to butterfly conformation of phenothiazine 22 , together with their attractive hole-transport characteristics have resulted in their use in dye sensitized solar cells (DSSCs) as photosensitizers 22 23 24 25 26 27 28 29 30 31 , as well as in organic thin film transistors and OLEDs 32 33 34 35 . Molecular aggregation and the degree of disorder in phenothiazine films has a strong impact on their optical properties 36 and better film-forming properties are usually observed in systems for which aggregate formation is less likely to occur 37 38 .…”

mentioning

confidence: 99%

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Crystallisation-enhanced bulk hole mobility in phenothiazine-based organic semiconductors

Shinde

Salunke

Candeias

et al. 2017

Sci Rep

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A series of three novel donor-acceptor systems based on C(3)-malononitrile-substituted phenothiazines was synthesised in good overall yields and their thermal, spectroscopic, and electrochemical properties were characterised. The compounds were prepared through a sequence of Ullmann-coupling, Vilsmeier-Haack formylation and Knoevenagel-condensation, followed by Suzuki-coupling reactions for introduction of aryl substitutents at C(7) position of the phenothiazine. The introduction of a donor unit at the C(7) position exhibited a weak impact on the optical and electrochemical characteristics of the compounds and led to amorphous films with bulk hole mobilities in the typical range reported for phenothiazines, despite the higher charge delocalisation as attested by computational studies. In contrast, highly ordered films were formed when using the C(7)-unsubstituted 3-malononitrile phenothiazine, exhibiting an outstanding mobility of 1 × 10−3 cm2 V−1 s−1, the highest reported for this class of compounds. Computational conformational analysis of the new phenothizanes suggested that free rotation of the substitutents at the C(7) position suppresses the ordering of the system, thereby hampering suitable packing of the new materials needed for high charge carrier mobility.

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Section: Resultssupporting

confidence: 89%

mentioning

confidence: 99%

Crystallisation-enhanced bulk hole mobility in phenothiazine-based organic semiconductors

Shinde

Salunke

Candeias

et al. 2017

Sci Rep

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“…EPT was synthesized as previously reported 7. Bis(2‐bromophenyl)sulfane12 and PhPT13 were synthesized following procedures similar to those used for the previously‐reported compounds. i PrPT and t BuPT were synthesized from bis(2‐bromophenyl)sulfane using a modified Buchwald‐Hartwig coupling reaction 14.…”

Section: Methodsmentioning

confidence: 99%

N‐Substituted Phenothiazine Derivatives: How the Stability of the Neutral and Radical Cation Forms Affects Overcharge Performance in Lithium‐Ion Batteries

et al. 2014

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Phenothiazine and five N-substituted derivatives were evaluated as electrolyte additives for overcharge protection in LiFePO4 /synthetic graphite lithium-ion batteries. We report on the stability and reactivity of both the neutral and radical-cation forms of these six compounds. While three of the compounds show extensive overcharge protection, the remaining three last for only one to a few cycles. UV/Vis studies of redox shuttle stability in the radical cation form are consistent with the overcharge performance: redox shuttles with spectra that show little change over time exhibit extensive overcharge performance, whereas those with changing spectra have limited overcharge protection. In one case, we determined that a C-N bond cleaves upon oxidation, forming the phenothiazine radical cation and leading to premature overcharge protection failure; in another case, poor solubility appears to limit protection.

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“…The current densities of Devices 1 and 2, which used 2T-NATA, were lower than those of the other devices that used HAT-CN owing to the poor hole mobility of 2T-NATA. 11,17 In addition, the current and power efficiencies of Device 1 were better than those of Device 2 because the thick structure of Device 2 induced triplet-triplet annihilation (TTA) and triplet-polaron annihilation (TPA) at the interface between the NPB HTL and the EML because the triplet bandgap of NPB is lower than that of FIrpic. [3][4][5]9 The adjusted EL intensity and CIE color coordinates are shown in Figs.…”

Section: Resultsmentioning

confidence: 97%

Control of the Color Coordinates of Blue Phosphorescent Organic Light-Emitting Diodes by Emission Zone

Rhee¹,

Nam²,

Ryu³

2013

ECS Solid State Letters

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The mechanisms of charge balance and tuning of the color coordinates in blue phosphorescent organic light-emitting diodes were studied by controlling the emission zone and electroluminescence (EL) spectrum. On the basis of the findings, this paper discusses different hole-injection and mobility factors such as the thickness of the hole injection layer (HIL), the HIL materials, the surface treatment, and the insertion of a buffer layer, which mainly enabled tuning of the color coordinates. The approximately 500-nmwavelength shoulder peak in the EL spectrum was influenced by the width and location of the emission zone, following the optical micro-cavity effect. Different emission zones were created by different types of hole injection and mobility, which simultaneously enhanced the device efficiency and tuning of the color coordinates.Although organic light-emitting diodes (OLEDs) 1-12 have attracted considerable attention owing to their low cost, simple process, and high efficiency, the application of blue OLEDs 1-7 has been limited by their poor long-term stability and short lifetime. Much effort has been devoted to developing novel materials and device architectures for blue phosphorescent OLEDs (PHOLEDs), 1-7 which are mainly used to meet the demands for high-efficiency and long-term stability in flatpanel displays and not necessarily because of their color coordinates and gamut. There have been many studies on methods of controlling the color coordinates using a tandem structure 10 and the micro-cavity effect in top-emission OLEDs 13 utilizing semi-transparent electrodes. However, very few studies have used blue PHOLEDs for color coordinate control.Moreover, there has been a tendency toward a trade-off between the efficiency and the color coordinates. Hsu et al. found that top-emitting, deep-blue-color OLEDs for Commission Internationale de l'Eclairage (CIE) 8,10 color coordinates (0.135, 0.056) exhibited a current efficiency of 1.5 cd/A, while an OLED for (0.132, 0.139) exhibited an efficiency of 3.8 cd/A. 13 High-efficiency devices using blue OLEDs have poor color coordinates compared to the National Television System Committee (NTSC) color coordinates (0.14, 0.08). It is actually not easy to simultaneously improve the device efficiency and color coordinates. Chen et al. have suggested that a higher hole mobility through emission layer (EML) resulting in an electroluminescence (EL) intensity change, color tuning, and a wider recombination zone was responsible for a longer device lifetime in blue OLEDs. 8 Nevertheless, to the best of our knowledge, only a few previous studies 2,3 on blue PHOLEDs using iridium -(III) bis-[(4,6-difluorophenyl)-pyridinato-N,C 2 ] picolinate (FIrpic) as a dopant considered the color coordinate performance.Here, we carried out a detailed investigation of how the performance of the device and the color coordinates were affected by changing the different types of hole injection and by the mobility of holeinjection-layer (HIL). Adjusted emission zones improved the device efficiency a...

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Electroluminescence Characteristics of a New Green-Emitting Phenylphenothiazine Derivative with Phenylbenzimidazole Substituent

Cited by 14 publications

References 18 publications

Crystallisation-enhanced bulk hole mobility in phenothiazine-based organic semiconductors

Crystallisation-enhanced bulk hole mobility in phenothiazine-based organic semiconductors

N‐Substituted Phenothiazine Derivatives: How the Stability of the Neutral and Radical Cation Forms Affects Overcharge Performance in Lithium‐Ion Batteries

Control of the Color Coordinates of Blue Phosphorescent Organic Light-Emitting Diodes by Emission Zone

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