Researchers from Sweden's Chalmers University have developed a new "double doping" process that basically doubles the efficiency of Polymer OLED emitter materials.

The researchers explain that doping in organic semiconductors operates through what is known as a redox reaction, in which the dopant molecule receives an electron from the semiconductor which increases the electrical conductivity of the semiconductor. The efficiency limit of current doped organic semiconductors has been limited by the fact that each dopant molecule was able to to exchange one electron only. In the new research it was shown how it is possible to move two electrons for every dopant molecule which increases the conductivity of the organic material.

The researchers explain that for the first time, they used a different polymer semiconductor, which has a lower ionisation energy compared to current polymer used. The researchers say that this was a relatively simple achievement - the new material simply allowed the transfer of two electrons to the dopant molecule.

The same technology could also be used to double the efficiency of organic solar panels (OPV) and bioelectronics devices.



What kind of efficiency?

Efficiency of electric conductivity doping can be doubled by "stronger" dopants. If we talk about OLED efficiency, we mean efficiency of light-generation. That is two different things. 

Atomic Force Microscopy for next-gen OLED processesAtomic Force Microscopy for next-gen OLED processes