An ultrabright bright quantum dot light-emitting diode (QLED) device and associated method of manufacture. The QLED device includes quantum dots (QD) as emitters and a mixture of metal oxide nanoparticles and alkali metal compounds for simultaneous electron injection and hole blocking to achieve charging balance at high driving current conditions. The ultrabright QLEDs are useful for many light source applications including, but not limited to display, solid state lighting, optical sensor, phototherapy, photomedicine and photobiomedicine.