Quantum Dots (QDs) can be used to make a white-light LED in several ways. Initially, the greatest benefit can be obtained by replacing just the red phosphor with red-emitting QDs, as shown in the figure on the left which plots actual spectra from an LED source with QD and phosphor downconverters. For a 3000K CCT and 80 CRI source, the benefit is over 20% improvement in spectral efficiency as measured by Luminous Efficacy of Radiation (LER). Higher CRI sources requiring more red in the spectrum will benefit even more. An all-QD solution will be possible in the near future to provide full spectral engineering capability, as shown on the plot on the right. In this case three QD colors are used to replace all the phosphor in the package, providing maximum benefit of >40% for a CRI of 95, representing a very high quality of light almost indistinguishable from an incandescent source.
This table summarizes the increase in spectral efficiency: