Morphology And Doping Position Of Sea Urchin-Like Gold Nanoparticles Study On Light Extraction Of OLED

Organic light-emitting diodes（OLEDs）have been developing for more than 40 years,and have achieved fruitful results in device structure design and material research and development.As the fourth generation of new light source,OLED’s market scale still fails to exceed that of LED,because OLED device efficiency and life are lower than that of LED.Therefore,improving the efficiency and service life of OLED devices is the key point that needs urgent attention for the development of OLED in the lighting field.One of the reasons for the low efficiency of OLED devices is that the light emitted from the device cannot be fully coupled to the air,and there are multiple mode losses.Therefore,in OLED lighting,it is very necessary to couple the light emitted by the light-emitting layer into the air through the light extraction technology.Metal nanoparticles are widely used in OLED devices due to their unique photoelectric properties,while sea urchin-like gold nanoparticles have stronger local surface plasmon resonance（LSPR）effect and scattering effect due to their special structure,which can be used as light extraction structure in OLED,thus improving device efficiency and extending device life.Therefore,the main research contents of this thesis include:（1）At first,three different kinds of sea urchin-like nanoparticles were synthesized by the seed-mediated method:short spined sea urchin-like gold nanoparticles,long spined sea urchin-like gold nanoparticles,and hollow sea urchin-like nanoparticles.The short spined sea urchin-like nanoparticles achieved the size control of sea urchin-like nanoparticles under the condition of changing the ratio of HAu Cl₄ and reducing agent,and the morphology was good,with the size of 140 nm 220 nm and 300 nm short spined sea urchin-like gold nanoparticles,while the size of long spined sea urchin-like gold nanoparticles and hollow sea urchin-like gold nanoparticles can only be controlled at 220nm and 300 nm respectively.（2）Then through the electromagnetic simulation modeling of the above five kinds of sea urchin-like gold nanoparticles,the near-field local characteristics and far-field scattering characteristics of different kinds of sea urchin-like gold nanoparticles are calculated using the finite-difference time domain method,and the simulation basis is provided for the experiment.（3）Finally,five types of sea urchin like gold nanoparticles were sequentially doped into different positions of white light OLED（WOLED）devices:the surface of the device,the interior of the device flexible substrate and the hole injection layer of the device,which ultimately achieved the device performance improvement.The hollow sea urchin-like gold nanoparticles doped in the flexible substrate achieved a 40.4%increase in current efficiency at the brightness of 1000 cd/m²;Power efficiency increased by 39%;The external quantum efficiency has been increased by 36%,and due to the LSPR effect of sea urchin-like nanoparticles,the device luminous intensity has been improved in the550～680 nm band.To sum up,this paper doped five kinds of sea urchin-like nanoparticles synthesized by seed mediated method in different positions of the device,which achieved the improvement of device efficiency,and provided an important idea for the preparation of high-performance OLED devices.