OLED ink jet printing: introduction and market status - Page 22

Heraeus is introducing new polymer OLED materials. The HIL-E grades is a combination of Hole Injection Layer and a high conductive electrode - and so provide an economic ITO alternative. These are PEDOT formulations designed for the OLED lighting industry.

The HIL-E materials feature excellent planarization properties and a refractive index that matches glass and plastic substrates. The formulations are also pH neutral. Regular and high work function grades are available. These polymer-based materials are suitable for slot-die coating, ink-jet printing and other deposition processes.

Merck has signed a cooperation and licensing agreement with Seiko Epson. According to the agreement, Epson will supply Merck with ink technology that dissolves Merck's soluble OLED materials so that they can be used for the production of printable OLED displays. This brings Merck closer to providing production-ready OLED printing materials.

The two companies will also continue their close cooperation to create a strong ink-formulation roadmap in order for Merck to commercialize and address current and future requirements of the OLED TV industry, including the creation of industry-standard inks for manufacturing OLED TVs using inkjet technology.

German startup Cynora unveiled a new mostly-solution-based flexible OLED prototype - aimed for smart packaging applications. Cynora developed the low-cost emitters (based on copper precursors) and developed the prototype in collaboration with InnovationLab (in a project titled cyFlex).

Cynora are now working towards the integration of the wiring into the thin film layers of the OLED. Cynora are using solution processing (coating and printing).

Digitimes reports that AUO has started to develop a printing process to make OLED panels, with hopes that this new process will lower the production cost and increase the material utilization. AUO is suffering from low (50%) yields in its current production process - which uses vapor deposition. The report suggests that AUO is also developing Oxide-TFT backplanes for OLEDs - but this isn't news - AUO unveiled an Oxide-TFT based 32" OLED TV prototype back in November 2011.

Actually all OLED makers are looking into more efficient production processes based on printing so this is hardly a surprise. It's likely that it will take some years before we'll start seeing printed OLED panels on the market though.

According to a report from Nihon Keizai, Panasonic has taken steps to streamline its R&D and put more focus on OLED TV development. The company plans to invest ¥30 billion ($385 million) in a pilot AMOLED production line in Himeji (this was already reported in April). According to the report Panasonic wants to use PLEDs and ink-jet printing in its upcoming fab. Panasonic's P-OLED/Ink-jet development dates back to the OLED TV joint-venture with Sumitomo in 2009.

Sony OLED TV prototype

The report also details the collaboration between Panasonic and Sony. The two companies have quite different technologies - Panasonic with its P-OLED and printing processes and Sony with small-molecules and VTE. It is claimed that Sony will mostly supply capital for Panasonic, and not technology. Sony's own OLED technology will be used though by Japan Display to make small sized panels.

Researchers from the Fontys University in The Netherlands have demonstrated that patterned plasma treatment of substrates gives them better control over inkjet printed structures (which results in higher quality printing).

The researches have used tailored wettability using InnoPhysics uPlasmaPrint technology that can locally change surfaces from hydrophilic to hydrophobic and vice-versa, creating patterns that make droplets spread in only one direction while restraining them in the other direction. Printed lines created in this way have both a very high homogeneity and a well-controlled width (without this technology the inkjet spreads in all directions which creates broader lines). In the research they used PixDro's LP-50 R&D inkjet printing platform.

Merck is a global pharmaceutical and chemical company based in Germany, working on high performance OLED materials. We're happy to post this third interview with Merck's OLED unit VP, Dr. Udo Heider:

Q: Dr. Heider, thanks for taking the time to do yet another interview with us.

Thanks Ron. I do appreciate this opportunity to communicate about our recent Merck OLED activities.

I'm assuming that Merck is still focused on Solution Processable materials. Can you give us a short update on the current status of your materials?

Yes, of course, we are very diligently focused on solution processable materials development based on our customers requests. As communicated in the past, Merck is working on solution processable small molecule materials. Our chemists have devised ways to redesign an evaporable small molecule and optimize its performance within a soluble device stack, applicable to the various soluble "printing" process windows.

The Holst Centre and Solvay report advances in flexible OLED lighting panels. They present a bendable 69 cm² OLED panel that features 30 lm/W efficiency at 1000 cd/m²:

Konica Minolta has successfully developed a high-accuracy inkjet head capable of 1-picoliter drop size, the first for printed electronics applications. The new print head utlilizes the company's proprietary MEMS technologies for the first time. KM will start offering the new inkjet printhead (the KM128SNG-MB) in sample quantities by this spring.

The new print head is resistant to various inks required for industrial applications and suitable to use with low-viscosity inks. It can be used for all sorts of applications, including OLED display patterning and OLED lighting thin air coating.

Tanaka Kikinzoku Kogyo announced that their conductive silver ink is now available commercially, and they say they are the first company to offer such a prOduct. The silver ink is hardened using UV light - there's no need for thermal hardening, and can be used in a broad range of products - including OLED panels.

The ink needs to be exposed to UV light for around 0.3 seconds, and it then hardens instantaneously even at room temperature to form a current-carrying circuit. For a 5 µm film thickness, wiring was formed with an electric resistivity of 10^-3 ohm cm. The ink can be used on both a glass base and a flexible base (PVC or PET films).