Disentangling the role of linear transition dipole in band-edge emission from single CdSe/ZnS quantum dots: Combined linear anisotropy and defocused emission pattern imaging

Abstract

Photon statistics in enhanced fluorescence from a single CdSe/ZnS quantum dot in the vicinity of silver nanoparticles Appl. Phys. Lett. 95, 193106 (2009); 10.1063/1.3259792Blinking suppression of colloidal CdSe/ZnS quantum dots by coupling to silver nanoprisms

Measurement of Three-Dimensional Dipole Orientation of a Single Fluorescent Nanoemitter by Emission Polarization Analysis

“…The agreement with the theoretical histogram for 2D dipoles is not very good, possibly because of a mixture of 1D and 2D dipolar emission as suggested in Refs. [47] and [48]. This can be explained by an energy splitting, at room temperature, smaller than k B T between the degenerated AE1 L and the linear 0 L transitions, which allows a linearly polarized emission [45].…”

Probing the Fluorescence Dipoles of Single Cubic CdSe/CdS Nanoplatelets with Vertical or Horizontal Orientations

“…For the moment, we have considered that the nanoplatelet dipole could be modeled either by pure 1D and 2D dipoles, and finally excluded the 1D case. However, for other semiconductor nanoparticles, it has been reported that the emission might be a sum of a 2D dipole and a third orthogonal 1D dipole with different oscillator strengths [16][17] . However these discussions relied either on the assumption that the dipole orientation was known 16 or on very delicate quantitative analysis of the polarization and defocused image 17 .…”

“…However, for other semiconductor nanoparticles, it has been reported that the emission might be a sum of a 2D dipole and a third orthogonal 1D dipole with different oscillator strengths [16][17] . However these discussions relied either on the assumption that the dipole orientation was known 16 or on very delicate quantitative analysis of the polarization and defocused image 17 . In the following section, we will demonstrate that, for these nanoplatelets, we can exclude the emission from a third dipole to less than 5%.…”

“…Spherical quantum dots, on the other hand, behave as an incoherent sum of 2 orthogonal dipoles (« 2D dipole ») [13][14][15] . Some results however suggest an intermediate behavior (sum of 1D and 2D dipoles) for dots-in-rods 16 and quantum dots 17 , while 1D-dipole emission has also been reported for quantum dots and attributed to ligand effects 18 .…”

Consequence of shape elongation on emission asymmetry for colloidal CdSe/CdS nanoplatelets

“…In both cases, polarized emission can be observed, with the degree of polarization depending of their orientation (with polarization degree higher for 1D dipoles). Analyses using polarimetric methods, sometimes combined with defocused imaging or decay curves, have demonstrated 2D-dipole behavior for spherical core-shell quantum dots [1][2][3][4] and dot-in-plate structures [5], and 1D-dipole behavior for nanorods [6] and dot-in-rods [7], with intermediate 1D+2D behavior for some structures [8,9]. These studies have found dipolar nature (1D or 2D) to be related both to the symmetry and degeneracy of the electron-hole transition dipole, and also to the shape of the nano-object, even when the Bohr radius of the exciton is smaller than the size of the nanoobject, a size difference that should made the dipolar transition insensitive to spatial confinement.…”