Navillum Nanotechnologies is unique among quantum dot producers because of our proprietary low-temperature synthesis methods. The conventional routes for synthesizing quantum dots uses a high temperature (typically 240 – 350 ⁰C), rapid injection process. And that is the problem… The high temperature process makes producing large batches of quantum dots with consistent quality a technical challenge because quantum dot growth happens within seconds. Quantum dot growth is slowed down by cooling the reaction from these high temperatures which takes time. QDs will continue to grow faster in any hot portions of the reaction vessel and slower in the cooler portions causing the size distribution of the final product to broaden. Broad size distribution means undesirable broad photoluminescence emission (i.e., large full width at half maximum or FWHM). The alternative, combining many small batches, is also challenging because any variation in the peak emission wavelength or emission bandwidth batch to batch will cause the emission of the combined batches to broaden significantly.
The Navillum synthesis approach avoids these problems all together since it is based on a perturbed, low-temperature equilibrium (well below 200 ⁰C) between quantum dot growth and dissolution. The process is remarkable for a number of reasons, not the least of which is its energy efficiency. Through the creation of a thermodynamic equilibrium, it provides us with an unparalleled degree of control over the net nanoparticle growth rate, ultimate mean quantum dot size and shape, including breadth of the size distribution. This control is critical to the optical properties of the quantum dots and results in their bright, pure-color emissions. Our quantum dots are so uniformly sized that they routinely show strikingly more narrow bandwidths, i.e. smaller FWHM values than our competitors. Indeed, our competitors’ bandwidths are often so broad that they bleed out into the blurred, non-Gaussian spectral features sometimes referred to as “fat tails,” which for display applications results in diminished color gamuts. Navillum’s more narrow bandwidths (i.e. smaller FWHM value) results in wider (red/green/blue) color gamut achieved resulting in purer and more vivid colors emitted. Beyond that, the process scales up readily from small to large batch sizes without compromising quality. It is even amenable to continuous-flow processing for very large, industrial-scale production runs.
It is also important to note that Navillum is adept at utilizing different QD shell configurations to enhance photoluminescence and to safeguard the chemical stability of QD cores. Single-semiconductor, multiple-semiconductor and graded-composition shells are all utilized to maximize down-conversion efficiency.