Mixing effect of hole-injecting and hole-transporting materials on the performance and lifetime of organic light-emitting devices

Kim, Youngkyoo; Oh, Eonseok; Lim, Hyun Sook; Ha, Chang‐Sik

doi:10.1063/1.2168014

Cited by 14 publications

(2 citation statements)

References 12 publications

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“…In this work, we have attempted to apply N,N′ ‐di(1‐naphthyl)‐ N,N′ ‐diphenyl‐(1,1′‐biphenyl)‐4,4′‐diamine (NPB) as a channel layer for UV‐sensing semitransparent OFETs by considering its molecular structure with asymmetric and twisted aromatic rings from the center of nitrogen atoms leading to a wide bandgap state for sufficient optical transparency in the visible light range as well as its good film‐forming characteristics as proven in the fields of OLEDs . To secure the optical transparency of all organic layers in OFETs, poly(methyl methacrylate) (PMMA) was employed as a gate‐insulating layer because it has no optical absorption above 365 nm (wavelength).…”

Section: Introductionmentioning

confidence: 99%

UV‐Sensing Semitransparent Organic Field‐Effect Transistors with Wide Bandgap Small Molecular Channel and Polymeric Gate‐Insulating Layers

Lee

Kim

et al. 2017

Adv Elect Materials

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This study demonstrates UV‐sensing semitransparent organic field‐effect transistors (OFETs) with wide bandgap small molecular channel and polymeric gate‐insulating layers. N,N′‐di(1‐naphthyl)‐N,N′‐diphenyl‐(1,1′‐biphenyl)‐4,4′‐diamine (NPB) is employed as the wide bandgap channel layer, while poly(methyl methacrylate) is introduced as the wide bandgap gate‐insulating layer. The performance of OFETs is optimized by NPB thickness control and thermal treatment. Results show that the best device performance (on/off ratio = 4.7 × 106 and hole mobility = 4.2 × 10−5 cm2 V−1 s−1) is achieved by thermal treatment of the 130 nm thick NPB layers at 70 °C for 30 min leading to a noticeably changed surface morphology in the NPB layers. The optimized OFETs exhibit excellent operation stability without hysteresis, while those with semitransparent silver electrodes deliver quite a good transparency. The semitransparent OFETs can sensitively detect a UV light with high stability even though no photoresponse is measured under a visible light.

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Section: Introductionmentioning

confidence: 99%

UV‐Sensing Semitransparent Organic Field‐Effect Transistors with Wide Bandgap Small Molecular Channel and Polymeric Gate‐Insulating Layers

Lee

Kim

et al. 2017

Adv Elect Materials

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“…But, for all these great potentials, device stability remains to be a key issue to be contended by all of us in the OLED community. Many methods have been proposed to improve the lifetime of OLEDs, such as using improved materials with high T g [2], good encapsulation to minimize the penetrations of water vapor and oxygen [3], using mixed OLED materials to improve the morphological stability of the thin film [4], or fabricate a single-host structure without apparent interface and charge accumulation by using multifunctional bipolar transport material like MADN [5].…”

Section: Introductionmentioning

confidence: 99%

P‐182: Lifetime Enhancement by Fabrication of a Doped Graded‐emission Layer in Organic Light‐emitting Diodes

Chuang

Cheng

Chen

et al. 2011

Symp Digest of Tech Papers

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We report an improved doped graded-emission layered structure (IG-EML) which can be readily fabricated by a conventional research thermal-evaporation coater and enhance device lifetime. This is demonstrated by doping fluorescent yellow emitter EY53 in the host matrix formed by programmed continuous mixing of a typical hole transporting material (e.g. NPB) and an electron transporting material (e.g. BAlq). Compared with the conventional bi-layer (B-EML), mixed-emission (M-EML) and a typical graded-emission (G-EML) device, the novel IG-EML doped OLEDs offer significant advantage in operational device stability T 50 (more than 4.8 times than that of the B-EML structure) without compromising its current efficiency.

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Synthesis of poly(N‐9‐ethylcarbazole‐exo‐norbornene‐5,6‐dicarboximide) for hole‐transporting layer in hybrid organic light‐emitting devices

Choi

Hwang

Kim

et al. 2010

J. Polym. Sci. A Polym. Chem.

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We synthesized new polynorbornene dicarboximide (PCaNI) functionalized with hole‐transporting carbazole moieties and its copolymer (PCaNA) by ring‐opening metathesis polymerization (ROMP), where the PCaNA was further reacted with 3‐amino‐triethoxysilane to prepare PCaNI/silica hybrid. We also investigated the feasibility of PCaNI and PCaNI/silica hybrid (PCaSi) as a hole‐transporting material for hybrid organic light emitting devices (HOLEDs). To improve the performance of the PCaNI‐based HOLEDs, N,N′‐diphenyl‐N,N′‐(3‐methylphenyl)‐[1,1′‐biphenyl]‐4‐4′‐diamine (TPD) was also introduced into the PCaNI matrix. Results showed that PCaNI exhibited high glass transition temperature (∼260 °C) and high optical transparency in the visible region. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of PCaNI were measured as 5.6 and 2.2 eV, while the TPD‐doped PCaNI showed 5.7 eV (HOMO) and 2.6 eV (LUMO). The PCaNI/silica hybrid nanolayers showed excellent solvent resistance due to the formation of covalent bonds between ITO and PCaNI. The HOLEDs with PCaNI/TPD or PCaSi/TPD hybrid nanolayers exhibited relatively higher luminance (∼10,000 cd/m2), lower operating voltage (∼6.5 V at 300 cd/m2), and higher current efficiency (∼2.7 cd/A). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

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Mixing effect of hole-injecting and hole-transporting materials on the performance and lifetime of organic light-emitting devices

Cited by 14 publications

References 12 publications

UV‐Sensing Semitransparent Organic Field‐Effect Transistors with Wide Bandgap Small Molecular Channel and Polymeric Gate‐Insulating Layers

UV‐Sensing Semitransparent Organic Field‐Effect Transistors with Wide Bandgap Small Molecular Channel and Polymeric Gate‐Insulating Layers

P‐182: Lifetime Enhancement by Fabrication of a Doped Graded‐emission Layer in Organic Light‐emitting Diodes

Synthesis of poly(N‐9‐ethylcarbazole‐exo‐norbornene‐5,6‐dicarboximide) for hole‐transporting layer in hybrid organic light‐emitting devices

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