Dear Mr. Shekhar,

I have been working on polyaniline, a p-type conducting polymer, for more than 5 years where I have managed to synthesize it and manipulate its morphology and use it in mono-layered hybrid solar cells.

However It is easier to create a p-type conducting polymer than an n-type. Usually the partial reduction of a polymer results in an n-doping of the polymer. However such a material is unstable in air. That's why nowadays researchers are trying to find an efficient and low-cost technique to produce n-type conducting polymers to be used in a variety of applications.

Hope that my answer was helpful.

For more info check the following link:

http://www.tda.com/eMatls/ntype.htm

Regards

Michael Ibrahim, PhD

In conducting polymers usualy the mobility of the charge carriers determines the type of semiconductor (p-type or n-type). In thiophenes for instance, like P3HT, they usualy conduct holes much better (hole mobility much larger than electrons mobility) and therefore we use them as p-type polymers. In this case the n-type would not act as a good semiconducter.

nonetheless by chemical and electrochemical proccesses you can dope the polymer in both ways by either adding an electron or a hole. But as  mentioned it is important to find the specific polymer which is suitable to be am n-type as most conducting polymers will be much better p-type.

Issues as stability and oxidation and polymer characteristics (electrical, optical, mechanical, chemical etc) in the doped state as Michael Ibrahim has said before me is am important factor in fabricating these kind of materialsand doping them. 

Hi,

When you say p-type or n-type polymer you are referring to hole transport and electron transport properties respectively and they are normally not extrinsic semiconductors so not really n- or p-type. However, they can be electrically doped either unintentionally like P3HT (see https://www.researchgate.net/publication/264378517_Doping-Induced_Screening_of_the_Built-in-Field_in_Organic_Solar_Cells_Effect_on_Charge_Transport_and_Recombination) or intentionally using a high EA material such as F4TCNQ for p-type doping. There will be spontaneous charge transfer between the polymer ground state to F4TCNQ LUMO if there is enough energy offset. ( see DOI: 10.1002/adfm.200801761). 

For n-type doping a compound with very low ionization potential can be used and that has been done for C60 (see DOI 10.1007/s00339-008-4997-x).

As far as I know there is no dopant with such large EA can dope electron acceptors like fullernes with IP ~ 6. So they cannot be p-doped.

Best wishes.

Article Doping-Induced Screening of the Built-in-Field in Organic So...

Dear Shashank,

in polymers, the term electron acceptor and electron donor are more appropriate words to use. However, doping in polymers can be classified into oxidation doping to create p-type and reduction doping to create n-type. It is possible to invert the conductivity type by using either way. Some polymers are doped with a process called protonation.

I hope that can help.