Universal p-type doping of organic electronic materials
Researchers at the University of Oxford have developed a new technique for doping organic semiconductors which involves low cost chemicals which result in no damaging by-products being formed.
The new technique is compatible with both vapour and solution processes for forming semiconductor films and enables graded doping within a material to be achieved. This novel technology is the subject of a patent application. Oxford University Innovation is now seeking commercial partners to adopt the new technology and support its future development.
Organic semiconductors are an important component in the semiconductor device market, often being used in light-emitting diodes, field effect transistors and photovoltaic devices. Organic semiconductors are frequently doped in order to enhance their charge transporting properties. Many different types of dopants can be used including p-type dopants consisting of elemental species, covalent solids, acids and small molecules.
However, several problems exist with known techniques for doping organic semiconductors and other hole transporting materials. It is common for p-type dopants to be expensive due to their complex chemical structures. They can also be susceptible to moisture and the ambient atmosphere which limits the overall lifetime of the semiconductor.
For some dopants, by-products are formed with metals or oxygen which may impact the stability of devices. The efficiency of some p-type dopants can also be very low, and it may be that substantial amounts of a p-type dopant are required in order to increase the free carrier concentration within the host semiconductor.
In order to address these problems, researchers at the University of Oxford have devised a new method and system of p-type doping of organic materials which is both compatible with vapour and solution-based production.
The advantages of the of the new technique include:
- a clean chemical reaction which does not form undesirable by-products;
- the ability to dope a wide range of different semiconductors;
- the ability to use low-cost doping material;
- an easier to handle process with reduced toxicity; and
- the possibility to select separately the counter ion which is to be introduced to the doped semiconductor.
Further, the devised technique enables graded doping such that a concentration of dopant ions is higher on one side of a semiconductor film compared with the other.
Such an arrangement can already be achieved with vapour deposited semiconductor films. However, for more cost-effective solution processed films, no simple route for aching graded doping has yet been realised.
This technology is the subject of a patent application.
Oxford University Innovation is now seeking commercial partners to adopt the new technology and support its future development.
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