Controlling the Emission Properties of Quantum Rods via Multiscale 3D Ordered Organization

Figure 3

Fluorescence emission properties of CdSe/CdS QRs interacting with each other in various dried states. The nanoparticles are either part of supracrystals ( in grey), obtained by letting the droplet dry in between a coverslip and a microstructured PDMS stamp (see Figure 2), or part of aggregates with local liquid crystal order ( in green), obtained without stamp. Emitters dispersed in water at 2.5 μM ( in red) are used as references since they correspond to noninteracting nanoparticles. Measurements were all performed on the confocal setup, and the excitation wavelength was set at . (a) Fluorescence emission spectra for 18 nm long quantum rods (QR₁₈) for the two dried samples, (gray) and (green), and for the aqueous suspension, . (b) Corresponding fluorescence emission decay curves. (c) Fluorescence emission spectra for 40 nm long quantum rods (QR₄₀) for the two dried samples, (gray) and (green), and for the aqueous suspension, . The fluoresence emission spectrum was almost superimposed with the baseline, so it was magnified by a factor 10 in the insert for sake of clarity. (d) Corresponding fluorescence emission decay curves.

(a)

(b)

(c)

(d)