Preparation Of Self-assembled Monolayer And Research On Its Modification To The OLED Anode

Self-Assembled Monolayer?SAM?is a spontaneous formation of the thermodynamic stability and orderly arranged monolayer film by a membrane reaction between molecular and solid base.It has many advantages,such as simple operation,good stability and orientation,etc,so it has wide application in organic electronics and electrochemical electrode.This paper designed a novel hole-transporting materials TPD-SAc,with TPD as the main body,sulphur ester as anchor groups,methylene as bridging groups,and formed SAM on gold surface,then applied SAM to modify the anode of OLED,aiming to improve the contact between inorganic and organic surface.We synthesized TPD-SAc through the Vilsmeier reaction,reduction reaction and Mitsunobu reaction,then optimized Vilsmeier reaction by adjusting the ratio,temperature and time and optimized Mitsunobu reaction by adjusting the reation systems and order of feeding,thus the total yield was 30.8%.TPD-SAc formed SAM on gold surface with the help of triethylamine,then studied the mechanism of formtation by fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy,confirming the formation of S-Au bond between molecular and gold surface,and studied the physical and electrochemistry properties by contact angle measurement,atomic force microscope,ultroviolet photoelectron spectrometer and electrochemistry measurement,finding the angle of inclination was about 45o,adsorbing capacity was 2×10^-10 mol·cm^-2,the work function of gold was decreased0.2eV and SAM has obvious influence on the charge transfer in solution.Prepared three types of organic light-emitting diode?OLED?device,and the effect on device performance of the introduction of the SAM and gold buffer layer was studied.Experiments showed that the device 1 modified by SAM and device 2 that gold as a buffer layer had much improved performance than device 3 that without modification in various aspects.The brightness of device 1?7303.90 cd/m²?was 1.69times and 1.78 times greater than device 2?4315.43 cd/m²?and device 3?4106.14cd/m²?respectively,and the current efficiency of device 1?8.49 cd/A?is 1.92 times and 2.29 times greater than device 2?4.42 cd/A?and device 3?3.70 cd/A?and the stability of color coordinates are also improved.The enhencment influence of SAM on the anode of OLED can be attributed to improvement of hole injection.