DIRECT, NON-CONTACT CONDUCTIVITY MEASUREMENTS OF
ORGANIC SEMI-CONDUCTOR FILMS BY THz-TDS

 

Okan Esenturk*1 and Edwin J. Heilweil2

1 okan.esenturk@nist.gov, Department of Chemistry and Biochemistry, UMCP

2 edwin.heilweil@nist.gov, Optical Technology Division, Physics Lab, NIST

 

Abstract: Intrinsic photo-conductivities of various poly(3-hexylthiophene) (P3HT) polymers and polymer blends with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) were measured and compared by using optical pump-THz probe spectroscopy. Our optical studies confirm previously observed increases in conductivity with increasing molecular weight of the P3HT polymer with deviations associated with the polymers dispersion index. Measured intrinsic conductivity values are found to increase with increase in the index. In addition we have observed significant enhancement in the charge generation and carrier concentration of the blends of P3HT with electron acceptor PCBM. An optimum mixture of P3HT:PCBM was found to be ~4:1 in weight ratio.