A structure with a transistor is disclosed comprising a substrate, a gas barrier layer on the substrate, and a transistor on the gas barrier layer. The transistor can include an oxide semiconductor layer. The oxide semiconductor layers can comprise In—Ga—Zn—O. A display, such as a liquid crystal display, can have such a structure.

Structure with transistor

Polymers for flexible displays: From material selection to device applications

Thin-film electronics intimately laminated onto the skin imperceptibly equip the human body with electronic components for health-monitoring and information technologies. When electronic devices are worn, the mechanical flexibility and/or stretchability of thin-film devices helps to minimize the stress and discomfort associated with wear because of their conformability and softness. For industrial applications, it is important to fabricate wearable devices using processing methods that maximize throughput and minimize cost. We demonstrate ultraflexible and conformable three-color, highly efficient polymer light-emitting diodes (PLEDs) and organic photodetectors (OPDs) to realize optoelectronic skins (oe-skins) that introduce multiple electronic functionalities such as sensing and displays on the surface of human skin. The total thickness of the devices, including the substrate and encapsulation layer, is only 3 μm, which is one order of magnitude thinner than the epidermal layer of human skin. By integrating green and red PLEDs with OPDs, we fabricate an ultraflexible reflective pulse oximeter. The device unobtrusively measures the oxygen concentration of blood when laminated on a finger. On-skin seven-segment digital displays and color indicators can visualize data directly on the body.

Ultraflexible organic photonic skin

https://pure.rug.nl/ws/files/6774271/2012OrgElectrGrossiord.pdf

Degradation mechanisms in organic photovoltaic devices

Flexible organic light emitting diode (OLED) will be the ultimate display technology to customers and industries in the near future but the challenges are still being unveiled one by one. Thin-film encapsulation (TFE) technology is the most demanding requirement to prevent water and oxygen permeation into flexible OLED devices. As a polymer substrate does not offer the same barrier performance as glass, the TFE should be developed on both the bottom and top side of the device layers for sufficient lifetimes. This work provides a review of promising thin-film barrier technologies as well as the basic gas diffusion background. Topics include the significance of the device structure, permeation rate measurement, proposed permeation mechanism, and thin-film deposition technologies (Vitex system and atomic layer deposition (ALD)/molecular layer deposition (MLD)) for effective barrier films.

https://iopscience.iop.org/article/10.1088/0268-1242/26/3/034001/pdf

Thin film encapsulation for flexible AM-OLED: a review

We have developed a coating technology to reduce the moisture permeation rate through a polycarbonate plastic film substrate to below 1×10−5g∕m2∕day using plasma-enhanced chemical vapor deposition. Unlike other ultrahigh barrier (UHB) coatings comprised of inorganic and organic multilayers, our UHB coating comprises a graded single hybrid layer of inorganic and organic materials. Hardness and modulus of the inorganic and the organic materials are tailored such that they are similar to those of typical glass-like materials and thermoplastics, respectively. In this barrier structure, the composition is periodically modulated between the inorganic and the organic materials, but instead of having distinctive interfaces between two materials, there are “transitional” zones where the coating composition changes continuously from one material to another. Our UHB coating also has superior visible light transmittance and color neutrality suitable for the use of display and lighting device substrates.

Transparent hybrid inorganic/organic barrier coatings for plastic organic light-emitting diode substrates

The use of polycarbonate film substrates enables fabrication of applications, such as flexible display devices, lighting devices, and other flexible electro-optical devices, using low cost, roll-to-roll fabrication technologies. One of the limitations of bare polycarbonate material in these applications is that oxygen and moisture rapidly diffuse through the material and subsequently degrade the electro-optical devices. This article summarizes recent results obtained at GE Global Research to solve the oxygen and moisture diffusion issue. It will be shown that through the application of thin, dense, plasma-based inorganic coatings one can significantly reduce the oxygen and moisture permeation rate through polycarbonate films. However, as a result of defects that are commonly present in these inorganic coatings there is a limit to the performance of such barrier coatings. To further improve the barrier performance, advanced barrier coatings comprising both inorganic and organic materials have been developed. Both modeling and experimental results will be presented that explain why these hybrid material barrier coatings are capable of reaching ultrahigh barrier performance.

Ultrahigh barrier coating deposition on polycarbonate substrates

The use of plastic film substrates for organic electronic devices promises to enable new applications, such as flexible displays and conformal lighting, and a new low-cost paradigm through high-volume roll-to-roll fabrication. Unfortunately, presently available substrates cannot yet deliver this promise because of the challenge in achieving the required combination of optical transparency, impermeability to water and oxygen, mechanical flexibility, high-temperature capability, and chemical resistance. Here, we describe the development and performance of a plastic substrate comprising a high heat polycarbonate film combined with a unique transparent coating package that is aimed at meeting this challenge.

A Transparent, High Barrier, and High Heat Substrate for Organic Electronics

A composite article with at least one high integrity protective coating, the high integrity protective coating having at least one planarizing layer and at least one organic-inorganic composition barrier coating layer. A method for depositing a high integrity protective coating.

High integrity protective coatings

The invention relates to composite articles comprising a substrate and additional layers on the substrate. According to one example, the layers are selected so that the difference in the coefficient of thermal expansion (CTE) between the substrate and a first layer on one side of the substrate is substantially equal to the CTE difference between the substrate and a second layer on the other side of the substrate. The stress caused by the CTE difference and/or shrinkage on one side of the substrate during heating or cooling is balanced by the stress caused by the CTE difference on the other side of the substrate during heating or cooling. Such stress balancing can reduce or minimize curling of the substrate.

Tae Won Kim

Papers

Transparent hybrid inorganic/organic barrier coatings for plastic organic light-emitting diode substrates

Ultrahigh barrier coating deposition on polycarbonate substrates

A Transparent, High Barrier, and High Heat Substrate for Organic Electronics

High integrity protective coatings

Multilayer device and method of making