Size-Dependent Non-FRET Photoluminescence Quenching in Nanocomposites Based on Semiconductor Quantum Dots CdSe/ZnS and Functionalized Porphyrin Ligands
Figure 8
Comparison of the experimentally determined quenching rate constants with respect to the calculated values for “QD-porphyrin” nanocomposites in toluene at 295 K. (Left axis) Averaged (for molar ratios ) quenching rate constant for QD PL quenching induced by attached H2P(m-Pyr)4 molecules for one uncapped (open marker) and four ZnS-capped (solid markers) CdSe QD. corresponds to the CdSe core diameter and to the ZnS ML thickness. (Right axis) Calculated size-dependent curves for the probability density functions of a 1 s electron at the outer interface () between the ZnS shell and the environment for various ZnS shell thicknesses for a potential barrier energy of 2 eV between the CdSe core and the ZnS shell, and a barrier energy of 4 eV between the ZnS shell and the matrix. The constant (see (7)) has been adjusted with respect to to fit the experimental value for QD with nm and the number of ZnS monolayers ML. QD parameters: 1— nm, number of ZnS monolayers ; 2— nm, ; 3— nm, ; 4— nm, ; 5— nm, .
