Stable, High-Conductivity Polymeric Ink for Advanced Flexible Electronics

Electrically conducting polymers have made possible the development of flexible and lightweight electronic components such as organic biosensors, solar cells, light-emitting diodes, transistors, and batteries. The electrical properties of the conducting polymers can be tuned using a method known as “doping.” In this method, various dopant molecules are added to the polymer to change its properties. Depending on the dopant, the doped polymer can conduct electricity by the motion of either negatively charged electrons (an n-type conductor) or positively charged holes (a p-type conductor).

Today, the most commonly used conducting polymer is the p-type conductor PEDOT:PSS. It has several compelling features such as high electrical conductivity, excellent ambient stability, and most importantly, commercial availability as an aqueous dispersion. However, many electronic devices require a combination of p-types and n-types to function. At the moment, there is no n-type equivalent to PEDOT:PSS.

Researchers have now developed a conductive n-type polymer ink that is stable in air and at high temperatures. The new polymer formulation is known as BBL:PEI. The combination of PEDOT: PSS and BBL:PEI opens new possibilities for the development of stable and efficient electronic circuits.

The new n-type material comes in the form of ink with ethanol as the solvent. The ink can be deposited by simply spraying the solution onto a surface, making organic electronic devices easier and cheaper to manufacture. In addition, the ink is more eco-friendly than many other n-type organic conductors currently under development that contain harmful solvents.

Large-scale production is feasible; however, work remains to be done to adapt the ink to various technologies.