Researchers improved polymer films, the basis for organic electric. The new material is promising for increasing the capacity in lithium polymer batteries, solar cells, and modernization of organic field-effect transistors. The description and results of the study are published in the Optik.
Organic electronics use organic materials to manufacture microcircuits and other electronic devices. Polymeric materials are used as semiconductors in such electronics and replace traditional electronic components based on silicon, copper, etc. In particular, polyvinyl alcohol (PVA) polymer films are highly dielectric and charge-accumulating. They are used in lithium polymer batteries and capacitors, organic light super-capacitors emitting diodes (OLED), and solar cells. But they are still inferior to traditional silicon-based batteries in terms of energy storage efficiency. The group of scientists figured out how to make the PVA film more energy-efficient by adding another polymer – polyethylene glycol (PEG) – to its composition.
“The energy capacity of batteries directly depends on the dielectric permittivity of the polymer film. We analyzed how the dielectric properties of the PVA film change when PEG is added in different concentrations – 1, 3, 5, 10, 15, and 20%. Impedance spectroscopy analysis showed that even at a one-percent concentration of PEG in the composition, the film’s ability to accumulate electricity increases several times. Consequently, the use of a mixture of PVS and PEG will increase the electrical capacity of lithium polymer batteries used in cell phones, digital devices, and, in particular, hybrid electric cars,” said Ahmed Henaish, senior researcher at the UrFU Nanomaterials and Nanotechnologies Research and Education Center.
The improved polymer mixture can also be used in other organic electronic elements. For example, thanks to its new composition current losses in organic field effect transistors (OFET) are reduced.
“A feature of the field effect transistor is its low power consumption at fairly high currents. Now there is an increased interest in the application of OFET in new industrial devices. However, organic transistors still have a number of drawbacks, the elimination of which depends, among other things, on improving the properties of polymer materials,” said Ahmed Henaish.
In the future, the researchers plan to study the dielectric properties of thin polymeric nanocomposites made of PVA with aluminum addition.
Reference
Polyvinyl alcohol and polyethylene glycol are man-made organic polymers. The main feature of organic polymers is the presence of carbon atoms in their composition. Electronics with organic polymers differ from classic silicon cells in their lightness, flexibility and transparency. In the production of such polymers technologies of polymerization, condensation and chemical influences are used. For example, polyvinyl alcohol is synthesized from simple and complex polyvinyl ethers using alkaline or acid hydrolysis, and polyethylene glycol is obtained by influencing ethylene oxide with alkaline catalysts and glycols. Cellulose is a typical example of a natural polymer.
The first conducting polymers were created in the 1970s and 80s by Alan MacDiarmid of the University of Pennsylvania, Alan Heeger of the University of California, and Hideki Shirakawa of the University of Tsukuba. They won the Nobel Prize in Chemistry in 2000 for this discovery. The discovery of the high electrical conductivity of modified polymers was an important step toward the creation of new electronics based on organic materials.
