JournalArticle SearchList By TopicSubmit ArticleRegister
ResourcesWhite PapersGlossaryStock TrackerPresentations
19 Feb 2009 | Germany
More work on inorganic transistors: Progress at Evonik
In the Science-to-Business Center Nanotronics of Creavis Technologies and Innovation, the strategic research unit of Evonik`s Chemicals Business Area, is developing materials for thin film transistors (TFTs). Apart from printed conductors Evonik develops dielectrics and inorganic, oxidic semiconductors.
In the field of printed dielectrics, Evonik has experience in evaluating derivates and special grades of PMMA for the use in TFTs. Due to the amorphous character of the polymer, film homogeneity of PMMA is much better than of many other polymeric systems. The huge variation of copolymers and different polymer architectures provide a lot of opportunities to tune this organic material to special solvent systems and to make this class of materials accessible to several printing technologies like inkjet or screen printing.
In the field of printed semiconductors, Evonik is developing new n-type inorganic oxides as high performing semiconductor materials that can be processed by several printing technologies. Compared to organic systems, these materials show a more stable and higher performance in the device, but usually processing temperature is above 150°C, and therefore low cost substrates like PET cannot be used.
Based on mobilities of non-solution processed films of ZnO between 55 to 155cm2/Vs (pp. 33-38, Physik Journal 5 (2006) Nr. 1) which up to now, could not be achieved with organic systems, Evonik obtained solution processable material systems with mobilities up to 0,1cm2/Vs at 150°C and more than 2cm2/Vs at 260°C (see figure 1) in 2008. These very promising values let them feel certain that they can reach mobilities higher than 1cm2/Vs at temperatures below 150°C in the near future (see figure 2).
Figure 1: Semiconductor development.
Figure 2: Target range for mobility and processing temperature of semiconductors.
Figure 3 shows the typical transfer characteristic of their n-type semiconductor materials in a bottom gate configuration. Due to good filming properties of the semiconducting materials they can also be used in top gate devices with Evonik's special grade PMMA. The combination of the two components (dielectric and semiconductor) provides the chance to offer not only one part of the device but a high performing material system for the application and printing process.
Figure 3: Transfer characteristics of gen3 semiconductor system.
In the field of transparent conductors Evonik has developed a new mask-less process based on an inkjet-printing and screen-printing to structure transparent and conductive layers (TCL) applicable as electrodes for display, lighting, and sensor devices. This new approach is based on dispersions of nano-scaled indium tin oxide (ITO) material and features manufacturing advantages: reduction of process steps, increase of material yield, compatibility with variable layouts and designs as well as substrate size and scalability for large areas by using direct printing instead of vacuum sputtering and etching.
New sintering methods have been adjusted to the limited thermal stability of typical polymer-type substrates like PET, however they are equally suitable for glass-type substrates. The transparent conductor combines low sheet resistance below 100 Ω/sq. and a transmittivity above 90 % on glass. This approach can be part of a new enabling technology for all printed devices. The performance of a Novaled PIN OLEDTM stack that uses this ITO TCL used as an anode is shown as an example in figure 4.
Figure 4: Current efficiency of a Novaled PIN OLEDTM stack on an inkjet printed, transparent conductive ITO anode.
Evonik Industries AG
Evonik Industries AG is the creative industrial group from Germany, which operates in three business areas: Chemicals (formerly Degussa), Energy and Real Estate. They provide specialty chemicals, power generation from hard coal to renewable energies, and are one of the largest private residential real estate companies.
Creavis Technologies & Innovation addresses the establishment of profitable and sustainable new businesses for Evonik and their focus is to enhance the Evonik portfolio by building high-value businesses in new technologies and/or new markets.
Based on their developments, Creavis Technologies & Innovation will provide printing inks for semiconductors (p-type and n-type), conductors, transparent conductors, dielectrics, insulators and memory materials.
Furthermore, the company offers the adoption of these materials to suitable printing technologies such as gravure, flexo, ink jet, screen printing.
For more attend Printed Electronics Europe 2009 .
Covering forecasts by application, challenges, opportunities, players and manufacturing technology appraisalTransistors, PV, batteries/supercapacitors, conductors, sensors, metamaterials, memristors, displays and lighting
- Graphene Markets, Technologies and Opportunities 2014-2024
- Inorganic and Composite Printed Electronics 2014-2024
- Conductive Ink Markets 2014-2024: Forecasts, Technologies, Players
- Barrier Layers for Flexible Electronics 2015-2025: Technologies, Markets, Forecasts
- Metal Oxide TFT Backplanes for Displays 2014-2024: Technologies, Forecasts, Players
- Electroactive Polymers and Devices 2013-2018: Forecasts, Technologies, Players
- New Opportunities for Gold: Conductive Inks for the Electronics Industry 2013-2019
- Functional Materials for Future Electronics: Metals, Inorganic & Organic Compounds, Graphene, CNT
- Touch Screen Modules: Technologies, Markets, Forecasts 2012-2022
- Printed, Organic & Flexible Electronics Forecasts, Players & Opportunities 2014-2024
- Internet of Things (IoT): Business Opportunities 2015-2025
- Wearable Technology 2014-2024: Technologies, Markets, Forecasts
- Transparent Conductive Films (TCF) 2014-2024: Forecasts, Markets, Technologies
- Printed Electronics for Healthcare, Cosmetics and Pharmaceuticals 2014-2024
- Smart Packaging Comes To Market: Brand Enhancement with Electronics 2014-2024
- Printed and Thin Film Transistors (TFT) and Memory 2013-2023: Forecasts, Technologies, Players
- Printed Electronics - Customer Sourcebook & Routes to Profit
Graphene Markets, Technologies and Opportunities 2014-2024
Inorganic and Composite Printed Electronics 2014-2024
Conductive Ink Markets 2014-2024: Forecasts, Technologies, Players
Barrier Layers for Flexible Electronics 2015-2025: Technologies, Markets, Forecasts
Metal Oxide TFT Backplanes for Displays 2014-2024: Technologies, Forecasts, Players
Electroactive Polymers and Devices 2013-2018: Forecasts, Technologies, Players
New Opportunities for Gold: Conductive Inks for the Electronics Industry 2013-2019
Functional Materials for Future Electronics: Metals, Inorganic & Organic Compounds, Graphene, CNT
Touch Screen Modules: Technologies, Markets, Forecasts 2012-2022
Printed, Organic & Flexible Electronics Forecasts, Players & Opportunities 2014-2024
Internet of Things (IoT): Business Opportunities 2015-2025
Wearable Technology 2014-2024: Technologies, Markets, Forecasts
Transparent Conductive Films (TCF) 2014-2024: Forecasts, Markets, Technologies
Printed Electronics for Healthcare, Cosmetics and Pharmaceuticals 2014-2024
Smart Packaging Comes To Market: Brand Enhancement with Electronics 2014-2024
Printed and Thin Film Transistors (TFT) and Memory 2013-2023: Forecasts, Technologies, Players
Printed Electronics - Customer Sourcebook & Routes to Profit
New solar cells serve free lunch
New imaging capability key to extending battery lifetime, capacity
New formulation leads to improved liquid battery
New imaging capability key to extending battery lifetime, capacity
Ulm battery research center now complete
Focus on hybrid applications and offshore