Characteristics of Organic Light-Emitting Devices by the Surface Treatment of Indium Tin Oxide Surfaces Using Atmospheric Pressure Plasmas

We investigated the gate-bias and temperature dependence of the voltage-current (V-I) characteristics of dinaphtho[2,3-b:2$,3$-d]thiophene with MoO 3 /Au electrodes. The insertion of the MoO 3 layer significantly improved the device performance. The temperature dependent V-I characteristics were evaluated and could be well fitted by the Schottky thermionic emission model with barrier height under forward-and reversebiased regimes in the ranges of 33-57 and 49-73 meV, respectively. However, at a gate voltage of 0 V, at which a small activation energy was obtained, we needed to consider another conduction mechanism at the grain boundary. From the obtained results, we concluded that two possible conduction mechanisms governed the charge injection at the metal electrode-organic semiconductor interface: the Schottky thermionic emission model and the conduction model in the organic thin-film layer and grain boundary.

Section: Introductionmentioning

confidence: 99%

Gate-bias and temperature dependence of charge transport in dinaphtho[2,3-b:2′,3′-d]thiophene thin-film transistors with MoO₃/Au electrodes

Shaari

Naka

Okada

2018

“…In these modification methods, plasma surface modification has been found to be an extremely attractive technique for ITO. 20,21) In spite of high surface modification efficiency, the currently available plasma modification processes for ITO films are mainly limited to low-pressure plasmas and have several major limitations, such as the restricted volume of the plasma reactor and the requirement for one or more vacuum and chemical cycles. To overcome these limitations, atmospheric-pressure plasma treatment can be seen as a potential candidate for surface modification.…”

Section: Introductionmentioning

confidence: 99%

Surface Treatment and Characterization of Indium–Tin-Oxide Thin Films Modified Using Cyclonic Atmospheric-Pressure Plasma

Tsai¹,

Huang²

2013

The surface characteristics of indium–tin-oxide (ITO) films modified using cyclonic atmospheric-pressure plasma were investigated by static contact angle (CA) analysis as well as atomic force microscopy (AFM). The surface modification effects of plasma operational conditions including treatment time, plasma power, gas flow rate, and distance of nozzle to the substrate on the ITO surface features were examined. Cyclonic atmospheric pressure plasma-modified ITO films showed a significant decrease in static water contact angle. The surface energy calculated by the Owens–Wendt method primarily increased from the polar component after cyclonic atmospheric pressure plasma treatment. The glow feature and luminous plasma species in the cyclonic atmospheric pressure plasma were identified by optical emission spectroscopy (OES). Atomic force microscopy revealed that the cyclonic atmospheric pressure plasma-modified ITO surface showed a slightly increased surface roughness and a similar morphology to the untreated ITO surface. As a result, it is believed that this cyclonic atmospheric pressure plasma alters the ITO surface physicochemical features, which can in turn improve ITO films performance for various applications.

“…1,2) It is expected that the interface between the ITO and an organic layer could critically affect the electrical properties of the organic device, such as carrier injection, recombination efficiency, and current instability. 3,4) Recently, many researchers have reported that an ITO with a scanning electron microscope (SAM) can improve the lifetime and electroluminescence efficiency of an OLED.…”

Section: Introductionmentioning

confidence: 99%

“…Indium tin oxide (ITO; SnO 2 -In 2 O 3 ) has been widely used in optical devices, particularly in organic light-emitting diodes (OLEDs) and organic thin-film transistors (OTFTs), because of its high transmittance, low resistance, and simple patterning process. 1,2) It is expected that the interface between the ITO and an organic layer could critically affect the electrical properties of the organic device, such as carrier injection, recombination efficiency, and current instability. 3,4) Recently, many researchers have reported that an ITO with a scanning electron microscope (SAM) can improve the lifetime and electroluminescence efficiency of an OLED.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Surface Modifications by Wet and Dry Methods on Indium Tin Oxide Using Self-Assembled Monolayers

Jee

Kim

Park

et al. 2010

We developed a self-assembled monolayer (SAM) surface modification of an indium tin oxide (ITO; SnO 2 -In 2 O 3 ) by a dry method for ink-jet printing processes and compared this with the SAM surface modifications by wet and dry methods. We focused on an analysis of the work function increase and changes in chemical bonding at the ITO surface interface with the SAM. In addition, we demonstrated that the causes of the work function increase of the ITO were the binding energy changes of the oxygen atoms on the ITO surface and an improvement in the hole injection from the ITO with the SAM to an organic layer in the organic device. The SAM surface modification decreased the threshold voltage and increased the current density in the organic device. These changes were due to the energy barrier caused by the work function difference being removed at the interface between the ITO with a high work function (5.3 to 5.5 eV) and the organic layer. Additionally, it was observed that the current density and luminance characteristics of the device were improved by the SAM surface modification. There was less organic solvent contamination at the interface between the ITO and the SAM by the dry method because no organic solvent was used.