N,N′-Bis(3-methylphenyl)-N,N′-diphenylbenzidine, CAS number 65181-78-4, commonly abbreviated as TPD, is widely used as hole transport materials in organic electronic devices.
TPD is also used as a blue-violet light emitting material or host material on the phosphorescence organic light emitting diodes for its wide energy band being about 3.2 eV with highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) being 5.5 eV and 2.3 eV respectively [1, 2].
* Measurable with an optical spectrometer