Controlling energy level positions in hole conducting molecular films by additives
Hard X-ray photoelectron spectroscopy (HAXPES) has been used to study the bulk electronic structure of thin molecular films of the organic compounds 2,2′,7,7′-tetrakis (N,N’-di-p-methoxyphenyl-amine)-9,9’-spiro-bifluorene (spiro-OMeTAD), 4-(diethylamino)-benzaldehyde-1,1)-diphenyl-hydrazone (DEH) and poly(3-hexylthiophene) (P3HT). Molecular layers of these compounds are hole conducting, a property