Electroluminescence Properties Of The Dendritic Derivatives Containing Twisted Acenes Unit

In this article,we mainly study the Photophysical and electroluminescent properties of the dendritic derivative TTPy,TPPh,and DBPy containing a twisted acene structure.We also discussed the preparation process of the organic electroluminescent devices.The specific research contents is as follows:Firstly,we have explored the conditions for the fabrication of organic electroluminescent devices.The TPBi thickness parameter of the electron transport layer of the device shows that when the thickness of TPBi is 45 nm,the electron transport efficiency is the best.The holes injected from the anode and the electrons injected from the cathode are balanced by injection.The probability of forming an exciton is the largest and the leakage current is higher.Less,the device has the highest luminous efficiency.In addition,We studied the effects of spin coating speed and solution concentration of the light emitting layer TTPy on the performance of the electroluminescent device.In the experiment,we made a chlorobenzene solution of TTPy.The concentration of chlorobenzene solution were 10 mg/m L,15 mg/m L and 20 mg/m L.Then,the each solution concentration of light-emitting layer was spin-coated into a film at a speed of1000 to 6000 r/min to made the light-emitting layer film.The results show that when the solution concentration of 15mg/mL,speed of 3000 rev/min,TTPy thickness of 60nm,the device performance is optimal.At 8V drive voltage,the device has a high brightness of 20175 cd/m~2.The maximum photo efficiency is 11.1 cd/A.The maximum lumen efficiency is 8.72 lm/W and the maximum external quantum efficiency is 3.19%.Then,we compared and analyzed the photophysical properties of TTPy,TPPh and DBPy.We fabricated their electroluminescent devices and analyzed the experimental results.The results showed that their emission colors were different.TTPy emits green light with a peak wavelength of 517 nm.While TPPh and DBPy emits blue light and their peak wavelengths were447 nm.However,the electroluminescence performance of TTPy was significantly better than that of TPPh and DBPy.The analysis shows that the TTPy molecule with Pyrene as the central unit may have an efficient intramolecular energy transfer.Its dendrite unit effectively transfers energy to the central quinone molecule,which enhances the fluorescence emission of the molecule.Therefore,the optical performance of the central unit has great effect on the luminescent properties of the molecule.So the excellent central unit can greatly enhance the fluorescence performance of the molecule.The above studies show that as an organic light-emitting material,a dendritic derivative containing a twisted acene structure has excellent electroluminescence properties.And the central unit of the molecular affect the light-emitting properties and color of the material.This provides valuable guidance for the design and synthesis of new high-efficiency luminescent materials in the future.