In this work, a numerical investigation of an organic light-emitting diode (OLED) based on a bilayer architecture is presented, with particular emphasis on the influence of ZnO nanoparticles (ZNPs) concentration on charge transport, recombination dynamics, exci-ton formation, and luminescence performance. The studied device consists of a hole injec-tion layer combined with an electron transport and emissive layer based on Alq₃ doped with ZNPs. The impact of ZNPs concentration has been explicitly introduced into carrier mobility, dielectric permittivity, Langevin recombination rate, and radiative exciton decay. The simulation results show that increasing ZNPs concentration enhances charge bal-ance, recombination efficiency, exciton density, and luminescence power. Furthermore, the variation of ZNPs concentration from 0% to 10% in Alq₃ polymer layer increases the electron charge density from 0.65 x 1021cm-3 to 1.4 x 1021cm-3, the recombination rate from 1.25 x1025 cm-3 s-1 to 12.5 x1025 cm-3 s-1, the exciton density from 0.05 x 1015cm-3 to 0.75 x 1015cm-3 and the power of luminescence from 0.015W/μm2 to 0.75W/μm2. Since, the per-formance of Alq3-ZNPs-OLED is tenfold higher than of Alq3-OLED pure. These findings demonstrate that the incorporation of ZNPs is a key parameter for ameliorate and opti-mizing OLED performance which can serve many optoelectronic designs.