Synthesis And Photoelectrochemical Performance Study Of Several Hole-transport Materials

In 1978,Dr.CW Tang constructed the organic light-emitting diodes(OLED)by using organic materials and accomplished green electroluminescent emission.Since then,tremendous efforts are paid to this related field by worldwide scientists.It also became a hot spot in both research and industrial fields.Nowadays,the development of the OLED technology calls for the improvement of brightness,efficiency and lifetime of electroluminescent devices and also the electroluminescent materials.Hole transport materials play a vital role in electronic devices.It is still a issue to design and synthesis novel hole transport materials.In this paper,we design six novel hole transport materials containing the structure of triarylamines,carbazole and fluorene.The target compounds are synthesized by five steps;2,5-dibromonitrobenzene and phenylboronic acid are used as starting materials,the target compounds are synthesized by Suzuki coupling reactions,condogan reduction ring closure reaction,Ullmann reaction and Buchwald-Hartwig reaction.The structures of the compounds are characterized by 1H NMR,13 C NMR,IR and MS.The optical and electrochemical properties are studied,including thermal stabilities,UV-Vis spectrums,Fluorescent spectrums and the red-ox potentials.The results show that the six compounds have high glass transition temperature Tg,which indicates high thermal stabilities.The six compounds have large π-π conjugated systems,thus the maximum wavelengths in UV-Vis spectrum and Fluorescent emission spectrum has shifted to the long wavelengths(red shifts).The Fluorescence spectrum also shows that the six materials emit violet light and are good violet luminescent materials.The value of Band gap(Eg),HOMO energy level and LUMO energy level are calculated based on the red-ox potential of the six compounds.The data shows that all the materials enjoy a high value of HOMO,which make hole transport much easier.Thus,all of them will be benefit for the requirement of application as hole transport materials.