Organic light-emitting diodes (OLEDs) have progressively attracted generous attention because of their versatile applications in solid state lighting and full color displays. High-efficiency is crucial for OLED devices being energy saving and to have a longer lifespan. Numerous approaches have been attempted to attain high-efficiency OLEDs via newly synthesized organic materials, light-extraction structure design and energy-efficient device architectures. The organic materials used in optoelectronic devices have inherently low dielectric constant. In this work, we demonstrate a comprehensive model to quantitatively investigate the role of dielectric constant of the electron transporting material on the electric field distribution, charge drift and exciton recombination probability across the emissive layer (EML) and electron transport layer (ETL) in organic light-emitting diode via commercialized electrical simulation package SETFOS.