Run-guang Sun | PubMed Health

PubMed2006

[Surface enhanced Raman scattering spectra of carbozole and azobenzene disperse red polymer].

Surface enhanced resonance Raman scattering (SERRS) was employed to study the molecule alignment of carbozole and azobenzene disperse red polymer on the surface of rough silver thin film. According to the selection rule of optical transitions and experiment results, it was found that the surface geometry of carbozole and azobenzene disperse red polymer was: this was physical adsorption between the carbazole group, which is from the monomer of carbazole and nitro-group which is from the monomer of azobenzene on the surface of rough silver film, and there is almost no interaction between the principal chain and the substrate because of the distance. This geometrical configuration of CAP on the surface of the substrate was proposed to damage the stabilities and efficiency of azobenzene derivatives based optical storage devices.

English Abstract↗

PubMed2005

[Multiple emissions in organic electroluminescent device using a mixed layer as an emitter].

A organic electroluminescent device has been fabricated by using a mixed layer as an emitter. The configuration of the device is ITO/TPD/TPD: PBD(equimole)/PBD/A1, in which TPD (N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine) and PBD (2-(4'-biphenyl)-5-(4''-tert-butylphenyl)-1,3,4-oxadiazole) are used as hole transport material and electron transport material, respectively. Broad and red-shifted electroluminescent spectra related to the fluorescence of constituent materials were observed. It is suggested that the monomer, exciplex and electroplex emissions are simultaneously involved in EL spectra by comparison of the EL with the PL spectra and decomposition of the EL spectrum. The type of exciplex is the interaction between the excited state TPD (TPD*) and PBD in the ground state, and the type of electroplex is a (D+-A-)* complex by cross-recombination of hole on the charged hole transport molecule (D+) and electron on the charged electron transport molecule (A-). All types of excited states show different formation mechanisms and recombination processes under electric field. The change of emission strengths from monomer and excited complexes lead to a blue-shift of the emissive spectra with an increasing electric field. The maximum luminance and external quantum efficiency of this device are 240 cd x (cm2)(-1) and 0.49%, respectively. The emissions from exciplex or electroplex formation at the organic solid interface generally present a broad and red-shifted emissive band, providing an effective method for tuning of emission color in organic electroluminescent devices.

Biphenyl Compounds↗