F. Compounds containing an nucleus including: 1. unsubstituted and substituted N,N-bicarbazyls containing substituents in either or both carbazolyl nuclei such a. an alkyl radical including a substituted alkyl radical such as a haloalkyl or an alkoxyalkyl radical, b. a phenyl radical including a substituted phenyl radical such as a naphthyl, an aminophenyl or a hydroxyphenyl radical, c. a halogen