Strongly nonexponential time-resolved fluorescence of quantum-dot ensembles in three-dimensional photonic crystals

Abstract

We observe experimentally that ensembles of quantum dots in three-dimensional (3D) photonic crystals reveal strongly nonexponential time-resolved emission. These complex emission decay curves are analyzed with a continuous distribution of decay rates. The log-normal distribution describes the decays well for all studied lattice parameters. The distribution width is identified with variations of the radiative emission rates of quantum dots with various positions and dipole orientations in the unit cell. We find a striking sixfold change of the width of the distribution by varying the lattice parameter. This interpretation qualitatively agrees with the calculations of the 3D projected local density of states. We therefore conclude that fluorescence decay of ensembles of quantum dots is highly nonexponential to an extent that is controlled by photonic crystals.

Radiative Lifetime Modification of LaF3:Nd Nanoparticles Embedded in 3D Silicon Photonic Crystals

“…[ 18 , 19 ] In recent years, SE control by colloidal crystals and TiO 2 inverted opals has been demonstrated. [20][21][22][23][24][25] However, little work on SE has been conducted on silicon or other high refractive index contrast inverse opal PhCs that exhibit strongly modifi ed photonic DOS. [ 14 , 26 ] The emitters commonly used in the previous SE control studies were either organic dyes or colloidal quantum dots.…”

Spontaneous emission of near-infrared quantum dots controlled with photonic crystals

“…As the dots are not located at the same position they experience different densities of optical states [33]. Consequently, each quantum dot has a different spontaneous emission decay rate.…”

“…Furthermore, the translational symmetry of photonic crystals allows for the positioning of the emitter in any unit cell. Therefore, photonic crystals enable broadband control of spontaneous emission rates over large volumes of emitters [30][31][32][33][34][35][36].…”

“…A log-normal distribution of decay rates φ LN (γ) was successfully employed to fit decay curves measured from CdSe quantum dots inside titania inverse opals [33]. Here, the distribution φ LN (γ)…”

Controlling light emission with plasmonic nanostructures

“…The time-trace of the luminescence decay curve cannot be described by a single-exponential decay model. Instead, a distribution of decay times is used to quantify the luminescence decay of the quantum dots [115,116]. In general, decay curves of the luminescence I can be described with…”