Researchers at Linköping University and Umeå University have published their finding on developing a small and inexpensive organic electronics main power converter, paving the way to have organic and printed electronics powered by high voltage mains without the need for conventional power electronics.
The researchers said that printed electronics and OLED displays are now being found in a number of eco-friendly, energy-efficient applications. Previously, the "ideal" power solution was considered to be from organic solar cells, printed batteries or wireless transformers, which do works well in many cases. However, for fixed installations like lighting, signage or UV-blocking windows, it is more convenient to use a main-power wall socket. Until now this has not been possible, because the high voltage damages the organic electronics.
The project was led by Docent Deyu Tu from LiU's Division of Information Coding in collaboration with colleagues at Umeå University to find a solution to this problem.
As a result of this collaboration the researchers have now been able to demonstrate an organic converter that makes it possible to drive OLED devices with high luminescence, and to charge supercapacitors, both directly connected to main wall sockets.
Figure: Linköping University and Umeå University - Organic power electronic device
The converter consists of diode-connected organic thin-film transistors, operated at high voltages up to 325V, with the capacity to transform high alternating current (AC) to a selected direct current (DC).
The researchers consider this to be "pioneer" work of organic AC/DC converters, and a first stage in proving the concept of organic power electronics. To be used in real products, the power conversion efficiency needs to be improved.
The researchers said that plans are already underway to conduct follow-up projects to deal with the issues found in this project, and to move closer to commercially viable technology and products.
The project has received financial support from the Swedish Foundation for Strategic Research.
Docent Deyu Tu from LiU's Division of Information Coding, said, "For the first time in the world we have been able to demonstrate an AC/DC converter in organic electronics that functions at voltages above 300 V." Deyu Tu added, "Our converter paves the way for a wave of flexible, thin, cost-effective and eco-friendly solutions for the electronics of the future."
Design, fabrication and application of organic power converters: Driving light-emitting electrochemical cells from the AC mains
Christian Larsen | Robert Forchheimer | Ludvig Edman | Deyu Tu
The design, fabrication and operation of a range of functional power converter circuits, based on diode-configured organic field-effect transistors as the rectifying unit and capable of transforming a high AC input voltage to a selectable DC voltage, are presented. The converter functionality is demonstrated by selecting and tuning its constituents so that it can effectively drive a low-voltage organic electronic device, a light-emitting electrochemical cell (LEC), when connected to high-voltage AC mains. It is established that the preferred converter circuit for this task comprises an organic full-wave rectifier and a regulation resistor but is void of a smoothing capacitor, and that such a circuit connected to the AC mains (230 V, 50 Hz) successfully can drive an LEC to bright luminance (360 cdm−2) and high efficiency (6.4 cdA−1).