Effect of Hole Blocking Materials on the Performance of OLED

This work investigated green fluorescence Organic Light Emitting Diode (OLED) with four hole blocking materials HBMs. Aims to enhance color performance in QD-OLED panels to produces a set of light with red, green, and blue sub-pixels. The HBM examined in this scenario consist of: (4,7-diphenyl-1,10-phenanthroline)Bphen, Tris(8-hydroxyquinoline aluminium)Alq 3 , (2,2′,2″-(1, 3,5-benzinetriyl)-tris(1-phényl-1-H-benzimidazole)TPBi, (3-phényl-4(10-naphtyl)-5-phényl-1,2,4-triazole)TAZ. These holes blockings materials have different electron mobility and different hole-blocking barriers. A numerical model based on the drift-diffusion formalism was created to study electron and hole transport in OLEDs. The model includes continuity equations, conduction diffusion current, and the Poisson equation. The simulation showed the performance of each device was affected by these properties of each HBM. The width of the emission zone depends on the HBMs employed, and when the electron mobility increases the recombination zone is wide in the HBL. It was found that the device with Bphen, Alq3, TPBi, and TAZ have electrical and optical characteristics that are respectively: Langevin recombination rate (2.25 x10 25 cm -3 s -1 , 1.74 x10 25 cm -3 s -1 , 1.04x10 25 cm -3 s -1 ,1.79x10 24 cm -3 s -1 ), singlet exciton density (2.87x10 14 cm -3 , 2.2x10 14 cm -3 , 1.31x10 14 cm -3 , 0.22x10 14 cm -3 ), luminance (4700 cd/m 2 , 4500 cd/m 2 , 4400 cd/m 2 , 3200 cd/m 2 ). Our study provides a model system to examine the role of hole blocking materials on OLED optoelectronic properties.