Brightness-equalized quantum dots

Abstract

As molecular labels for cells and tissues, fluorescent probes have shaped our understanding of biological structures and processes. However, their capacity for quantitative analysis is limited because photon emission rates from multicolour fluorophores are dissimilar, unstable and often unpredictable, which obscures correlations between measured fluorescence and molecular concentration. Here we introduce a new class of light-emitting quantum dots with tunable and equalized fluorescence brightness across a broad range of colours. The key feature is independent tunability of emission wavelength, extinction coefficient and quantum yield through distinct structural domains in the nanocrystal. Precise tuning eliminates a 100-fold red-to-green brightness mismatch of size-tuned quantum dots at the ensemble and single-particle levels, which substantially improves quantitative imaging accuracy in biological tissue. We anticipate that these materials engineering principles will vastly expand the optical engineering landscape of fluorescent probes, facilitate quantitative multicolour imaging in living tissue and improve colour tuning in light-emitting devices.

Colloidal Quantum Dot Arrangement Assisted by Perylene Bisimide Self‐Assembly

“…The emission wavelength of QDs can be tuned synthetically by changing the size and composition of QDs . Since synthetic methods to obtain QDs with uniform diameters were developed, the detailed photophysical properties of QDs have been revealed at ensemble and single QD levels . For further progress in the field of nanocrystals, the surface chemistry of QDs has been modified to realize new functions and applications by introducing functional organic molecules such as photochromic molecules and fluorescent π‐conjugated molecules .…”

Quantum dot surface engineering: Toward inert fluorophores with compact size and bright, stable emission

“…To demonstrate this, we synthesized three QDs with identical ligands and identical shells (CdZnS), with cores differing only by their HOMO-LUMO energy gap (E H-L = 2.2, 2.3, or 2.4 eV) by tuning the composition of a ternary alloy HgCdSe QD core (see Fig. 5c) [107]. With a mixture of both X-type carboxylates and L-type amines, all three had similar QY values in aqueous solution.…”

“…Panel (a) is reproduced from reference [5] with permission. Panel (c) reproduced from reference [107] with permission.…”

Single‐Source Precursor Route for Synthesis of High‐Quality Green‐emitting Quantum Dots and Their Hydrophilic Surface Modification

“…Fluorescent quantum dots (QDs) have been widely used in light‐emitting diodes (LEDs) and biological field due to their unique optical properties such as size‐tunable emission colors, high extinction coefficient, and high photoluminescence quantum yields (QYs) . Despite these favorable properties, the size‐tunable QDs also have some undesirable properties for application.…”

“…Moreover, the size‐tunable fluorescent emitters are inevitably dissimilar in fluorescence brightness derived from the differences in extinction coefficient. As the consequence, the signal of the bluer QDs may be buried in background due to the much higher brightness of redder QDs in quantitative multicolour detection and imaging . Alloyed QDs such as CdS 1− x Se x have arisen as attractive candidates to overcome the drawbacks of binary QDs because their composition can range from CdS to CdSe by adjustment of the feed ratio of S and Se, and simultaneously, the emission is tuned without changing the size.…”