Synthesis And Properties Of Organic Light Emitting Material With D-Ï€-A Structure

High-performance organic light-emitting material is an important factor in thedevelopment of OLEDs, in particular red light material having excellent properties. So,eight novel organic photoelectric materials with D-π-A structure were designed andsynthesized in this thesis, including chain of triphenylamine derivatives, star-shapedtriphenylamine derivatives, monosubstituted linear carbazole derivatives and disubstitutedangle carbazole derivatives. The structure of the four series compounds were characterizedby1H NMR,13C NMR,FTIR and Elemental Analysis. Their UV-Vis spectra, fluorescencespectra, electrochemical behavior and thermal stability were studied respectively.(1)With triphenylamine and malononitrile as raw materials, two novel star-shapedtriphenylamine derivatives:(4-malononitrile-5-methyl-ene-2-Thienylphenyl)diphenylamine（N1）and Tri-(4-malononitrile-5-methylene-2-thienylphenyl)amine(N2). The resultsshow that N1and N2emit red fluorescence at652nm and664nm in solution, and its solidthin film also emit red fluorescence at670nm and685nm. Their HOMO energy levels(-5.51and-5.79eV) are matched with common hole transport material NPB (-5.20eV), itdemonstrate that they all have good hole transport property. The results of TG curves showthat their thermal decomposition temperatures (Td) are182and246℃, and they all havegood thermal stability.(2) With carbazole and malononitrile as raw materials, two novel monosubstitutedlinear carbazole derivatives:5-(N-ethyl-3-carbazolyl)-2-thienyl methylene malononit-rile(Q1),5-(N-butyl-3-carbazolyl)-2-thienyl methylene malononitrile(Q2) and5-(N-hexyl-3-carbazolyl)-2-thienyl methylene malononitrile. The results show that compoundsQ1~Q3emit yellow fluorescence at579nm in solution, and its solid thin film also emit redfluorescence at650nm. Their HOMO energy levels (-5.6、-5.8and-5.7eV) are matchedwith work function (-4.8eV) of positive electrode(ITO), so the barrier of hole transportingcan be effectively reduced and in favor of hole-transport. The results of TG curves showthat their thermal decomposition temperatures (Td) are354、350and203℃,and they allhave good thermal stability.(3) With carbazole and malononitrile as raw materials, two novel disubstituted anglecarbazole derivatives:3,6-bis-(4-fluorenylidenediazanyl-5-methylene-2-thienylphenyl)-N-ethyl carbazole(M1),3,6-bis-(4-fluorenylidenediazanyl-5-methylene-2-thienylphenyl)-N-butyl1carbazole(M2)1and13,6-bis-(4-fluorenylidenediazanyl-5-methylene-2-thienylphenyl )-N-hexyl carbazole(M1). The results show that compounds M1~M3emit yellowfluorescence at575nm in solution, and its solid thin film also emit red fluorescence at633nm、662nm and683nm. Their HOMO energy levels (-5.29、-5.24and-5.33eV) can beeffectively reduced and in favor of hole-transport. The results of TG curves show that theirthermal decomposition temperatures (Td) are224、307and320℃,and they all have goodthermal stability.In the above three series of compounds are synthesized with D-π-A conjugatedstructure and hole transport properties and good film-forming properties. Chain oftriphenylamine derivatives is better than star-shaped triphenylamine derivatives influorescence quantum efficiency, luminous intensity and thermal stability; Disubstitutedangle carbazole derivatives (M series) is better than monosubstituted linear carbazolederivatives(Q series) in luminous intensity; Carbazole derivatives have adwantages overtriphenylamine derivatives in terms of the optical properties and thermal stability.