Modification of anode surface in organic light-emitting diodes by chalcogenes

Katkova, Мarina A.; Ilichev, V. A.; Конев, А. Н.; Батенькин, М. А.; Pestova, I. I.; Vitukhnovsky, A. G.; Bochkarev, M. N.

doi:10.1016/j.apsusc.2007.06.033

Cited by 16 publications

(4 citation statements)

References 21 publications

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“…Intuitively, the expected propensity of WF was thought to increase as the contents of Te increased because the WFs of Te and bismuth telluride were reported with higher values than Bi [50,51]. The reported WF values of Bi, Te, Bi oxide and Te oxide are listed in Table 5 [50][51][52][53][54]. In other words, the WFs were expected to be BT70 > BT50 > BT30 > and BT20; however, our experimental findings deviated from such anticipation.…”

Section: Resultsmentioning

confidence: 58%

“…Figure 7 shows the atomic percentages of Bi and Te species with different oxidation states. Intuitively, the expected propensity of WF was thought to increase as the contents of Te increased because the WFs of Te and bismuth telluride were reported with higher values than Bi [50,51]. The reported WF values of Bi, Te, Bi oxide and Te oxide are listed in Table 5 [50][51][52][53][54].…”

Section: Resultsmentioning

confidence: 99%

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Etching and Compositional Ratio Effect on the Surface Properties of Bismuth Telluride Thin Films

Mun,

Han,

Yoon

et al. 2024

Surfaces

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Bismuth telluride has garnered considerable attention owing to its versatile properties applicable in thermoelectric and antibacterial domains, as well as its intriguing topological insulating properties. In this work, our group fabricated bismuth telluride thin films with various ratios using radio frequency magnetron sputtering. The surface properties of these thin films were thoroughly analyzed by employing a diverse array of analytical techniques, including X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), four-point probe and contact angle (CA) measurements. Specifically, our XPS findings indicated that Bi is more susceptible to oxidation than Te following Ar+-ion etching. Pure Te thin films exhibited the highest Rq value of 31.2 nm based on AFM and SEM results due to their larger grain sizes. The XRD patterns revealed a peak at 27.75° for thin films with 20% Te, attributed to its rhombohedral structure. Moreover, thin films with 30% Te yielded the highest weighted average work function with a value of 4.95 eV after etching. Additionally, pristine Bi and Te thin films demonstrated the most robust hydrophobic properties compared to intermediate-composition thin films, as determined by CA measurements.

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Section: Resultsmentioning

confidence: 58%

Section: Resultsmentioning

confidence: 99%

Etching and Compositional Ratio Effect on the Surface Properties of Bismuth Telluride Thin Films

Mun,

Han,

Yoon

et al. 2024

Surfaces

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“…The absorption spectra were measured with a Perkin Elmer 577 spectrometer, and emission spectra were recorded with a Perkin Elmer LS 55 spectrometer. SHESTAKOV et al Two layer OLED cells were prepared in a vacuum chamber by evaporation and condensation at 10 -5 torr according to the procedure described in [9]. A 20 nm layer of the hole conducting material TPD (N,N' diphenyl N,N' bis(3 methylphenyl) 1,1' biphenyl 4,4' diamine), a layer of rare earth complex (45 nm), a Bath (4,7 diphenyl 1,10 phenanthroline) electron transport and hole blocking layer (25 nm), and a layer of ytterbium metal of 150 nm thickness as a cathode were successively deposited on a glass plate coated with a layer of tin doped indium oxide (ITO) having a resistance of 10 Ω/cm 2 .…”

Section: Methodsmentioning

confidence: 99%

Synthesis, quantum chemical calculations, and luminescent properties of scandium, europium, gadolinium, and terbium 1-(2-pyridyl)naphtholate complexes

et al. 2012

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323Coordination complexes of rare earth metals attract considerable interest as promising emitter materials for organic light emitting diodes (OLEDs). In most cases, these complexes contain chelate O ∧ N or O ∧ O anionic ligands, which are derivatives of phe nol, hydroxyquinoline, β diketones, or carboxylic acids [1].It was found that substituents in the phenol, hydroxyquinoline, and diketone moieties and organic radicals in acids exert a great influence on photo and electroluminescent properties of the complexes, since they have a significant effect on the positions of HOMO, LUMO, and singlet and triplet energy levels of the compounds. Replacement of functional groups in the ligands makes it possible to vary both the effi ciency of luminescence and its spectrum and also affects the charge transport properties in electrolumi nophores. Numerous studies aimed at searching for the best organic ligands in the series of phenolates consisted in varying substituents on the phenol moiety [2][3][4][5][6]. To extend the range of search, we synthesized Sc, Eu, Gd, and Tb complexes with the ligands in which the phenolic fragment is replaced by naphthol and the frequently used 2 pyridyl functional group is retained. The choice of Sc, Eu, and Tb is due to the fact that the derivatives of these metals show the high est electroluminescent efficiency among rare earth elements [7]. The choice of Gd is associated with the specific luminescence characteristics of its com pounds, which can only be ligand centered owing to high lying resonance levels of the Gd 3+ ion, a property that allows the luminescence spectra of Gd derivatives to be used for band assignment in the complex spectra of other lanthanides. EXPERIMENTALThe syntheses were carried out under conditions that ruled out the contact with oxygen and air mois ture, using standard Schlenk glassware. Tetrahydrofu ran was dried over sodium benzophenone ketyl according to the standard procedure and withdrawn under vacuum immediately prior to use. Silylamides Ln[N(SiMe 3 ) 2 ] 3 were obtained from commercial sources. 1 (2 Pyridyl)naphth 2 ol was synthesized from 1 bromonaphth 2 ol and 2 bromopyridine according to the procedure developed previously for 2 (2 pyridyl)phenol [8]. IR spectra were recorded on a FSM 1201 Fourier transform spectrometer in the range of 400-4000 cm -1 . Samples were prepared as a mull in nujol. The absorption spectra were measured with a Perkin Elmer 577 spectrometer, and emission spectra were recorded with a Perkin Elmer LS 55 spectrometer.Abstract-By reactions of 1 (2 pyridyl)naphth 2 ol (pynH) with silylamides Ln[N(SiMe 3 ) 2 ] 3 (Ln = Sc, Eu, Gd, or Tb), the Ln(pyn) 3 complexes of the metals have been synthesized. Only the scandium complex in a THF solution has displayed photoluminescence (band with a maximum at 455 nm and a halfwidth of 65 nm). Electroluminescent properties have been revealed for the scandium and terbium complexes. In an ITO/TPD/Sc(pyn) 3 /Bath/Yb three layer light emitting diode, the scandium complex exhibits yellow-green luminescence ...

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“…The impact of the chalcogen X layer on the ITO surface has been investigated with a layer of TPD used as an HTL on the operating characteristics of OLEDs of composition ITO/X/TPD/Alq 3 /Yb (Alq 3 : tris (8-hydroxyquinoline) aluminium). 121 It was found that S layer decreases operating voltage and enhances operating stability of a device while Se or Te interlayers impair these characteristics. Recently, Helander et al demonstrated an air-stable chlorinated ITO (Cl-ITO) electrode with a work function of > 6.1 eV that provides a direct match to the energy levels of the active light-emitting materials (LEMs) in state-of-the-art OLEDs.…”

Section: Chemical Treatmentsmentioning

confidence: 98%

Progress in Modification of Indium-Tin Oxide/Organic Interfaces for Organic Light-Emitting Diodes

2013

Critical Reviews in Solid State and Materials Sciences

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The oxide/organic interfaces play crucial roles in the hole injection from the anode electrodes to the emitting organics in organic light-emitting diodes (OLEDs), and hence have strong impacts on the efficiencies and other properties of the devices. Indium-tin oxide (ITO) is currently the most popular anode material used in OLEDs due to several merits, such as good etch ability, good adherence, high transparency, low resistivity, and high work function. Interfacial engineering between the ITO electrode and the overlying organic layers is an important process to obtain the high performance of the diode devices. In this article, recent progress in modification of the ITO/organic interfaces is reviewed, as these interfaces are important to the development of the technologies aiming at improving the electroluminescence, and efficiencies as well as reducing the operation voltages of OLEDs. ITO/Organic interfacial properties can be controlled or modified by simply changing the surface properties of ITO using chemical or physical treatments, and by adding a buffer layer (e.g., metal, oxide, or organic thin films) between the ITO and hole transport or emitting organic layers. The literature data showed that the electroluminescence, efficiencies, and lifetimes of the OLEDs could be greatly increased and the operation voltage considerably decreased when the ITO/organic interfaces have been properly improved.

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Modification of anode surface in organic light-emitting diodes by chalcogenes

Cited by 16 publications

References 21 publications

Etching and Compositional Ratio Effect on the Surface Properties of Bismuth Telluride Thin Films

Etching and Compositional Ratio Effect on the Surface Properties of Bismuth Telluride Thin Films

Synthesis, quantum chemical calculations, and luminescent properties of scandium, europium, gadolinium, and terbium 1-(2-pyridyl)naphtholate complexes

Progress in Modification of Indium-Tin Oxide/Organic Interfaces for Organic Light-Emitting Diodes

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