MoS2-nanosheet/graphene-oxide composite hole injection layer in organic light-emitting diodes

2017-07-01
Park, Minjoon
Thang Phan Nguyen, Thang Phan Nguyen
Choi, Kyoung Soon
PARK, JONGEE
Öztürk, Abdullah
Kim, Soo Young
In this work, composite layers comprising two-dimensional MoS2 and graphene oxide (GO) were employed as hole injection layers (HILs) in organic light-emitting diodes (OLEDs). MoS2 was fabricated by the butyllithium (BuLi) intercalation method, while GO was synthesized by a modified Hummers method. The X-ray diffraction patterns showed that the intensity of the MoS2 (002) peak at 14.15A degrees decreased with increase in GO content; the GO (001) peak was observed at 10.07A degrees. In the C 1s synchrotron radiation photoemission spectra, the contributions of the C-O, C=O, and O-C=O components increased with increase in GO content. These results indicated that GO was well mixed with MoS2. The lateral size of MoS2 spanned from a few hundreds of nanometers to 1 mu m, while the size of GO was between 400 nm and a few micrometers. Thus, the coverage of the MoS2-GO composite on the ITO surface improved as the GO content increased, owing to the large particle size of GO. Notably, GO with large size could fully cover the indium tin oxide film surface, thus, lowering the roughness. The highest maximum power efficiency (PEmax) was exhibited by the OLED with MoS2-GO 6:4 composite HIL, indicating that similar contents of MoS2 and GO in MoS2-GO composites provide the best results. The OLED with GO HIL showed very high PEmax (4.94 lm W-1) because of very high surface coverage and high work function of GO. These results indicate that the MoS2-GO composites can be used to fabricate HILs in OLEDs.
ELECTRONIC MATERIALS LETTERS

Suggestions

TRANSPARENT GRAPHENE ANODES FOR ORGANIC LIGHT EMITTING DIODES
Sharif, Parisa; Oral, Ahmet; Çırpan, Ali; Department of Micro and Nanotechnology (2021-7-14)
This thesis presents a novel method for fabrication of OLEDs on a specific flexible PET substrate with graphene anodes, demonstrating low sheet resistance, high work function, and an extremely high luminance. Firstly, a single-layer graphene growth process with chemical vapor deposition (CVD) method is optimized. Flexible anodes are then fabricated by stacking 7-layers of graphene films and doped with nitric acid to reduce the sheet resistance. Modified few layer graphene anodes by 29 Ω/□ sheet resistance a...
Epoxy-based composites and coatings: improvement of multifunctional properties
Çaldıklıoğlu, Almira; Bayram, Göknur; Department of Chemical Engineering (2019)
The purposes of this study are to improve mechanical properties, thermal stability, resistance to flammability, electrical conductivity and hydrophobicity of epoxy (E) by incorporation of expanded graphite (EG) and titanium dioxide (T) particles. In this study, sonication with the use of solvent method was primarily determined for the epoxy-based binary composite and coating preparation. By this method, the epoxy composites and coatings were produced by changing EG concentration as 0.05, 0.1, 0.25, 0.5, 0.7...
Formation and characterization of infrared absorbing copper oxide surfaces
Arslan, Burcu; Erdogan, Metehan; Karakaya, İshak (2017-04-30)
Copper oxide formation has been investigated to combine the advantages of producing different size and shapes of coatings that possess good light absorbing properties. An aqueous blackening solution was investigated and optimum composition was found as 2.5 M NaOH and 0.225 M NaClO to form velvet copper oxide films. A two-step oxidation mechanism was proposed for the blackening process by carefully examining the experimental results. Formation of Cu2O was observed until the entire copper surface was covered ...
Phonon Mean Free Path in Few Layer Graphene, Hexagonal Boron Nitride, and Composite Bilayer h-BN/Graphene
Gholivand, Hamed; Donmezer, Nazli (Institute of Electrical and Electronics Engineers (IEEE), 2017-09-01)
In this study, ab-initio calculations were performed to obtain the phonon dispersions of seven different structures: single layer graphene, bilayer graphene, graphite, single layer h-BN, bilayer h-BN, bulk h-BN, and finally composite bilayer h-BN/graphene. Using these dispersions specific heat, group velocity, and single mode relaxation times of phonons were obtained to calculate their thermal conductivities, and mean free paths at room temperature. Calculated variables were used to understand the effects o...
Optimized spacer layer thickness for plasmonic-induced enhancement of photocurrent in a-Si:H
Saleh, Z. M.; NASSER, H; ÖZKOL, E; GÜNÖVEN, M; Abak, Musa Kurtuluş; Canlı, Sedat; Bek, Alpan; Turan, Raşit (2015-10-24)
Plasmonic interfaces consisting of silver nanoparticles of different sizes (50-100 nm) have been processed by the self-assembled dewetting technique and integrated to hydrogenated amorphous silicon (a-Si:H) using SiNx spacer layers to investigate the dependence of optical trapping enhancement on spacer layer thickness through the enhancements in photocurrent. Samples illuminated from the a-Si:H side exhibit a localized surface plasmon resonance (LSPR) that is red-shifted with the increasing particle size an...
Citation Formats
M. Park, T. P. N. Thang Phan Nguyen, K. S. Choi, J. PARK, A. Öztürk, and S. Y. Kim, “MoS2-nanosheet/graphene-oxide composite hole injection layer in organic light-emitting diodes,” ELECTRONIC MATERIALS LETTERS, pp. 344–350, 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/44488.