α-NPD, namely N,N′-Bis(naphthalen-1-yl)-N,N′-bis(phenyl)-2,2′-dimethylbenzidine, is a bis(triarylamine) that is joined by a 2,2'-dimethylbiphenyl unit. The only difference to NPB (N,N′-Bis(naphthalen-1-yl)-N,N′-bis(phenyl)benzidine) is that α-NPD has two extra methyl groups on the biphenyl bridging unit.
Bearing two triarylamine units, α-NPD is electron rich and known as a typical hole transporting material for organic electronics (OLEDs, OPVs). It is believed that the introduction of methyl groups in meta position on the central biphenyl unit of α-NPD is to create the distortion of the molecular geometry and consequently a decrease of the electronic conjugation as well as an increase of the band gap.
It is worth noting that α-NPD has also been identified as N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)benzidine in a lot of literatures. Please check the chemical structure, CAS (chemical abstract service) number and chemical name before you place the order with us.