Aluminum Nanoparticles for Photobleaching Resistance of Quantum Dots in Solution

We report on the optical properties of aluminum spherical nanoparticles exhibiting diameters ranging between 2 and 20 nm made by the reduction of aluminum ions in alkane solvents. In the UV-range, the extinction spectroscopy measurements unveiled well-defined surface plasmon resonances corresponding to the calculations performed using Mie theory. Furthermore, a photobleaching resistance effect appears for semiconductor quantum dots (QDs) in a solution containing aluminum nanoparticles. The particles allowed for a global increase in the number of photons emitted by a factor of up to 1.75 compared to QDs alone. Our investigation led us to the conclusion that the aluminum nanoparticles initially absorb a part of the emitted light and prevent the photobleaching of the QDs. Thus, these nanoparticles have the potential to be used as elementary building blocks for making more complex aluminum nanostructures for nanophotonics and also to protect emitters from photobleaching.