Abstract
To maximize the potential of poly(3-hexylthiophene) (P3HT) as a nonlinear optical material, we examined the conditions for fabricating thin films. The results indicate that the third-order optical susceptibility χ(3), which was determined by electroabsorption spectroscopy, is fourfold enhanced when thin films are drop cast from an anhydrous chloroform solution in an inert atmosphere, compared with the χ(3) of spin-coated thin films prepared in an ambient atmosphere. Fabricating the thin films in an O2- and water-free environment is essential for obtaining large χ(3) values. Under these conditions, we determined the maximum value of the imaginary part of χ(3) for P3HT to be 2.2 ×10-9 esu.