Study On Synthesis And Property Of The Novel Hole Transport Materials For Organic Light-Emitting Diodes (OLEDs)

The organic light-emitting device is showing its outstanding foreground of applications due to a novel display technology which is based on the central materials composing of organic hole transport materials(HTMs), organic electron transport materials(ETMs), and organic luminescent materials. Among of which, the thermal stability of the HTMs plays an important role in improving efficiencies and increasing lifetime of the diodes. In this thesis, basing on molecular designs, 2 series of triarylamine derivatives, potential hole-transporting materials, have been designed and synthesized.1 Anthryl Diamine DerivativesA series of anthryldiamine derivatives 9,10-bis (1-naphthylphenylamino) anthrace-ne ((1-NPA), 9,10-bis(2-naphthylphenylamino)anthracene((2-NPA), 9,10-bis (m-toly-lphenylamino) anthracene(TPA), 9,10-bis(diphenylamino)anthracene(PPA) were conveniently synthesized through changing the substituted groups by introducing 1-naphthyl, 2- naphthyl, methyl benzyl, and benzyl on the Nitrogen atoms. The best synthesis method was studied. The four compounds were synthesized from 9,10-dibromoanthracene and the corresponding diarylamine in the presence of Pd catalysis and sodium tert-butoxide of which the conditions optimitized that n[Pd(OAc)2]:n[P(t-Bu)3]=1:1.2, n[P(t-Bu)₃]: n[dibromoanthracene] is 0.48% in o-xylene while the reaction time lasted for 3hrs. The HPLC purities of compounds are: 98.3%, 99.18%, 98.70% and 98.40%.2 Diphenyl Diamine DerivativesA series of diphenyl diamine derivatives N, N'-dipheny-N, N'-bis (1-naphthyl) -1,-1'-diphenyl-4, 4'-diamine(NPB) , N, N'-dipheny-N, N'-bis (9- anthryl) -1,1'-diphenyl-4,- 4'-diamine(APB), N, N'-dipheny-N, N'-bis (triphenylamineyl) -1,1'-diphenyl-4, 4'-diamine(TPBD), and N, N'-dipheny-N, N'-bis (N-Phenyl-3-Carbazolyl) -1,1'-diphenyl-4, 4'-diamine(MPDPB),were conveniently synthesized through changing the substituted groups by introducing 1-naphthyl, 9- anthryl, triphenylamineyl, and N-Phenyl-3-Carbazolyl on the Nitrogen atoms. The best synthesis method was studied. The four compounds were synthesized from diphenylbenzidine(DPB) and the corresponding aromatic halides in the presence of Pd catalysis and sodium tert-butoxide in o-xylene under N₂ atomasph-ere of which the conditions optimitized that n[Pd(OAc)₂]:n[P(t-Bu)₃]=1:1.2, n[P(t-Bu)₃ ]: n[aromatic halides] is 0.24% in o-xylene while the reaction time lasted for 2～3hrs. The HPLC purities of these four kinds of compounds are: 99.8%, 99.1%, 97.8% and 99.5%.Their molecular structures were characterized by ¹H NMR spectroscopy and elemental analysis. Physical properties were examined by UV-Vis, PL and DSC spectra. Electrochemical properties were characterized by Cyclic Voltammetry (CV). Their thermal stability was studied by DSC analysis. The results indicated that the obtained compounds have good thermal stablibilities, fluorescence performances, and the appropriate HOMO trackenergy levels, which can be served as the hole transport materials in the OLEDs.