Aromatic Amines Organic Light-emitting Materials Synthesis And Performance Study

Materials based on arylamine are one of the most important materials for organic electroluminescent diodes (OLEDs). Molecules with triarylamine or N-aryl carbazole introduced in always show good hole-transporting ability. This dissertation focused on the synthesis of organic electroluminescent materials with high performance and fabrication of OLEDs with bright luminance and high efficiency. Molecules based on triarylamine and N-aryl carbazole were synthesized with naphthyl group introduced in. Red OLEDs and blue OLEDs were fabricated with these compounds as the emitting materials.Arylamine and isophorone derivatives as red organic electroluminescent materials studied in this dissertation are divided into the following series: a) triarylamine and isophorone derivatives (compound DPN-2CN, DPN-4CN and DNP-2CN); b) N-aryl carbazole and isophorone derivatives (compound PCz-2CN, PCz-4CN and NCz-2CN); c) triarylamine, benzothiazole and isophorone derivatives (compound BPPA-2CN and BPPNA-2CN). The chemical structures of these molecules were confirmed by ¹HNMR, IR, MS and elemental analysis. The performance of them were studied by UV-Vis absorption spectra, photoluminescence (PL) spectra, cyclic voltammetric (CV) experiments, scanning probe microscopy (STM) and atomic force microscopy (AFM). Two kinds of OLEDs, Dye-doped red OLEDs and Non-doped red OLEDs, were fabricated to study the electroluminescent properties of these materials. Devices fabricated with DPN-2CN, DNP-2CN, NCz-2CN, BPPA-2CN or BPPNA-2CN as the red emitter showed good EL performance.A series of blue electroluminescent materials based on triarylamine and benzothizole were designed and synthesized in this dissertation, N-(4-(benzo [d]thiazol-2-yl)phenyl)-N-phenylbenzenamine (BPPA), N-(4-(benzo[d]thiazol-2-yl) phenyl)-N-phenylnaphthalen-1-amine (BPPNA), 4-(benzo[d]thiazol-2-yl)-N-(4-(benzo[d]thiazol-2-yl)phenyl)-N-phenylbenzenamine (BBPA), N,N-bis(4-(benzo [d]thiazol-2-yl)phenyl)naphthalen-1-amine (BBPNA). The chemical structures of BPPA, BPPNA, BBPA and BBPNA were confirmed by ¹HNMR, IR, MS and elemental analysis. The characteristics of them were investigated by UV-Vis absorption spectra, PL spectra, CV experiments and STM. Non-doped blue OLEDs were fabricated with these materials as the blue emitter. Bright luminance and high efficiency were obtained for device with BBPA or BBPNA as the blue emitting layer. Device ITO/ NPB/ BBPA/ TPBI/ Al showed a brightness of 3610 cd m^-2 at the driving voltage of 16 V. The emission peak of this device is 454 nm and the CIE coordinates is (x = 0．19, y = 0．25) . A brightness of 1048 cd m^-2 , a current efficiency of 5．24 cd A^-1 , a power efficiency of 1．21 lm W^-1 and an external quantum efficiency of 2．88% at a driving current density of 20 mA cm^-2 were obtained for this device. Compound BBPNA has the similar structure with BBPA. BBPNA has N,N-diphenylnaphthalen-1-amine as the electron-donor while BBPA has triphenylamine. Device ITO/ NPB/ BBPNA/ TPBI/ LiF/ Al showed a brightness of 3821 cd m^-2 at the driving voltage of 16．5 V. The emission peak of this device is 460 nm and the CIE coordinates is (x = 0．19, y = 0．22) . A brightness of 293 cd m^-2 , a current efficiency of 1．47 cd A^-1 , a power efficiency of 0．61 lm W^-1 and an external quantum efficiency of 0．77% at a driving current density of 20 mA cm^-2 were obtained for this device. Device ITO/ NPB/ BBPNA/ LiF/ Al, with BBPNA as the emitting layer and electron transporting layer showed a brightness of 1430 cd m^-2 at the driving voltage of 13．0 V.