In this study, high performance of organic light emitting diodes (OLEDs) with a buffer layer of dicarbazole-biphenyl (CBP) film is demonstrated. With an optimal thickness of CBP (12 nm), the luminance efficiency of OLED is found to increase compared to the single-layer anode OLED. To study the performance of OLED using the buffer layer, we deposited CBP films of different thicknesses on the fluorine-doped tin oxide (FTO) surface and observed their $J–V$ and $L–V$ characteristics. Further analysis was carried out by making the host–guest combination within the light emitting region using iridium (III) complexes $\rm{(Ir(ppy)_{3})}$ as the dopant material to enhance the efficiency of the device. We also measure the sheet resistance, optical transmittance and surface morphology of both the single and bilayer electrode surfaces using the FE-SEM images. Here the maximum value of current efficiency is found to be 12.45 cd/A under optimised doped and quantum tunnelling conditions.