| The 21st century is an era of information and diversification.Most of the information obtained by people is obtained through visual means.In the field of display and lighting,the technology of organic light-emitting devices（OLEDs）has been widely concerned by the people,and OLEDs based on solution preparation can well meet the needs of the application market for large area and low cost.Since the phosphorescent organic electroluminescent devices were reported in 1987,the advantages of phosphorescent OLED technology have gradually shown:heavy metals in phosphorescent materials have strong spin-coupling effect,and can simultaneously use singlet excitons and triplet excitons for radiation transition luminescence,and theoretically its internal quantum efficiency can reach 100%.After decades of development,phosphorescent OLED devices have made rapid progress in efficiency and life.Platinum（Pt）with d8 electronic configuration located in group VIII of the periodic table usually forms metal platinum complexes by four-tooth coordination.This coordination method makes it have a rigid structure,which can effectively inhibit the rotation and vibration of metal complex molecules,and greatly reduce the non-radiation attenuation,which is conducive to the preparation of high-performance phosphorescent OLEDs.At present,the market is short of efficient and stable blue OLED materials,which to some extent hinders the development of blue and white OLED technology.In this paper,we have carried out a series of research based on blue light platinum complex as luminescent layer and phosphor sensitizer,in order to optimize and improve the performance of blue light devices and white light devices through device engineering strategies:（1）Preparation and performance optimization of blue phosphorescent devices based on binuclear platinum complex by solution method.Host-guest doped blue phosphorescent OLEDs prepared by the solution method of metal platinum complexes（Pt1 and Pt2）with different doping concentrations were designed and constructed.The blue phosphor device based on Pt2 can achieve the maximum lumen efficiency of 11.79 cd A-1 and the external quantum efficiency of 7.96%.In order to further optimize the device performance and reduce the efficiency roll-off problem,we use the solution method to construct a co-host doped phosphorescent device.When the doping concentration corresponding to the highest efficiency of single-body OLED is selected,we have successfully improved the efficiency rollover of the original device by using the double-body doping strategy while reducing the lighting voltage of the phosphorescent device（for example,the lighting voltage of the device based on Pt1 is reduced from 5.6 V to 4.5 V,and the lighting voltage of the device based on Pt2 is reduced from 5.4 V to 5 V）.（2）Preparation and characterization of phosphor sensitized thermal activation delayed fluorescence blue light device.Two kinds of platinum complex phosphors were used as sensitizers to sensitize the typical thermally activated delayed fluorescent materials（v-DABNA）,and the phosphor-sensitized thermally activated delayed fluorescent devices were prepared by adjusting the doping concentration in the solution.The photoluminescence and electroluminescence properties of v-DABNA sensitized by metal platinum complexes were studied in detail.The results show that the sensitized device is beneficial to the optimization of the device efficiency,efficiency roll-off and color purity of the constructed blue light device.The blue photosensitizer fabricated by Pt1 metal complex has achieved the device performance with a half-peak width of 16 nm and a maximum external quantum efficiency of 8.41%.Its efficiency is 6.5%higher than that before sensitization,and the rolling will be reduced by 11%.（3）Fabrication and characterization of white light devices based on binuclear platinum phosphors.In order to realize the ideal white light phosphorescent device,we have successfully prepared a high-performance white light OLED device based on two kinds of binuclear platinum complex phosphorescent materials by solution method using the blue light,yellow light and red light doping strategy.By optimizing the doping concentration of the light-emitting layer,the color coordinates（CIE）of the white light devices prepared are very close to the standard white light（0.33,0.33）,which are（0.32,0.34）and（0.34,0.35）respectively.In addition,a good device performance with external quantum efficiency of 7.40%and color rendering index of88 was achieved. |
