Flexible organic electronics
Organic electronics is a future-oriented technology for cost-effective and environmentally friendly manufacturing of electronic components based on conducting and semiconducting plastics. The hybrid electronics and patterning group works on the development of circuits built of organic transistors and manufactured by innovative processes on flexible substrates, as there are foil, paper, and textile.<br/> Depending on properties to emphasize, Organic Electronics is also referred to as Organic and Large Area Electronics (OLAE), Green Electronics, Flexible Electronics, and sometimes also Plastic Electronics.
The possible applications of organic electronics are as versatile as they are fascinating. They will lastingly change our daily lives:
- Autonomous intelligent environment by the Internet of Things: Printed RFID tags and memories
- Intelligent and safe packaging of sensitive products like food and drugs: smart labels for protection, logistics, safety from counterfeiting
- Save cooperation between man and machine: electronic skin for industry robots
- Sensor surfaces: active matrix addressing and in-pixel amplification in large area printed sensors
- Biomedicine: biocompatible transistors as biosensors in lab-on-a-foil sensor
- Wearable electronics: stretchable circuits for the control of sensors and displays
An organic thin film transistor (OTFT) is a 3-terminal device and requires 4 materials:
- an electrically conductive material for source, drain, and gate electrodes
- an insulating material as dielectric
- a semiconducting material for the active semiconducting layer
- as well as a flexible substrate
A transistor is termed “organic”, if at least the semiconducting layer consists of organic molecules as e.g. polymers. The use of organic transistors in more complex circuits requires very fast and high-performing single devices, which are achieved by optimising material system, design and manufacturing process.
At the Weiz location a cleanroom is available for fabrication of organic microelectronics, employing a number of different patterning and deposition methods such as nanoimprint lithography, printing techniques, vacuum deposition, and photo-lithography.
The organic electrochemical transistor (OECT) is a device where charge transport occurs not only by electrons but also by ions, as opposed to OTFTs. A great advantage of OECTs is their simple structure with all electrodes of the same material and in the same layer. There is no dielectric needed, only two materials are sufficient to fabricate functional OECTs:
- a conductive polymer (PEDOT:PSS), which can change its conductivity by several orders of magnitude via a redox reaction
- an electrolyte
This architecture enables operating voltages of less than one Volt and fast, simple manufacture by printing on plastic film or paper. As a consequence the road to extremely low-cost printed circuits is opened. However, due to ionic transport, OECTs are generally slower than OTFTs.