Studies On Property And Its Performances In Organic Light-emitting Devices Of New Organic AT Electron Transport Material

The electron mobility and the hole mobility in Organic light-emitting diodes(OLEDs)are quite different,while the electron mobility is relatively lower.Therefore,improving the electronic injection and transport abilities is very important for performance of the OLEDs.In this thesis,a new type of electronic transport materials,which are synthesized by our team,are characterized and applied in phosphorescent OLEDs.The main content in this thesis are as follows:(1)The properties of the new AT organic electronic transport materials,including the thermal stability,the energy level structure and the carrier mobility,are chracterized.It is shown that AT414 performs best among these new AT electron transport materials,which has the glass transition temperature is 171.07?,and high electron affinity.Its electron mobility is 7.4394×10-3 cm2/(V·s)under the condition of the electric field intensity of E=106V/cm,which is better than the known electron transport materials in the market.(2)The effects of different electron transport materials on the performance of the PhOLEDs are also studied.Here,the bipolar material E228 was used as the host material and MG05 was the guest/dopant material,which lead to the green emission,and different electron transport layers materials-(AT412,AT414,AT418,and AT420)and standard Alq3 electron transport material were employed.It is found that AT414,which has high stability,electron affinity and carrier mobility,enables the device performing best.Furthermore,Liq is doped into the electron transport layer.which is proved to improve the conductivity of the electron transport layer and reduce the electron injection barrier.Therefore,the tun-on voltage of the devices are reduced,and efficiency roll-off is suppressed due to the balanced electron and hole.