Study On Improving External Quantum Efficiency Of OLED By Concave Micro Pyramid Array

As a new type of lighting and display technology,organic light-emitting diode(OLED)has many advantages,such as flexible,low energy consumption,fast response,wide viewing angle,wide color gamut,self-luminous,light weight,large format,etc.OLED has great application prospects and commercial value in the field of lighting and display.In order to acquire better OLED,people are constantly improving OLED.When we evaluate the performance of OLED,we mainly focus on two aspects:internal quantum efficiency and external quantum efficiency.With the development of materials,the internal quantum efficiency of OLED is close to 100%.However,due to the total internal reflection and waveguiding phenomena,the external quantum efficiency only reaches about 20%,which hinders the further development of OLED.Increasing the roughness of the OLED substrate surface can improve the external quantum efficiency without affecting the radiation spectrum,which becomes a hot research topic.In this paper,a concave micro pyramid array is applied on the surface of OLED substrate to improve the external quantum efficiency of OLED.Firstly,we use optical software and modeling software to model OLED and different types of concave micro pyramid arrays.Then,Monte Carlo method is used to simulate the performance of concave micro pyramid arrays in improving the external quantum efficiency of OLED.We use 3D micro grayscale direct writing and nano-imprinting techniques to prepare the concave micro pyramid array.Finally,the concave micro pyramid arrays were attached to the surface of OLED substrate.The performance of the concave micro pyramid arrays in improving the external quantum extraction efficiency of OLED was evaluated by an optical system.Both the simulated and measured data show that the concave micro pyramid array can effectively improve the external quantum efficiency of OLED.