A simple biphasic route to water soluble dithiocarbamate functionalized quantum dots

Abstract

Hydrophobic trioctylphosphine oxide-functionalized CdSe quantum dots (CdSe-TOPO QDs) were transferred from organic solvent to aqueous solution via a simple yet novel biphasic ligand exchange process in one step, which involved the in-situ formation of hydrophilic dithiocarbamate moieties and subsequent ligand exchange with TOPO at the chloroform/water interface. The resulting water dispersible, dithiocarbamate functionalized CdSe QDs (i.e., D-CdSe) exhibited an increased photoluminescence (PL) quantum yield as compared to the original CdSe-TOPO QDs, suggesting an effective passivation of dithiocarbamate ligands on the QD surface. The D-CdSe QDs were then mixed with hydroxyl terminated TiO 2 nanoparticles. A decrease in the PL of the mixture was observed, indicating a possible charge transfer from the D-CdSe QDs to the TiO 2 nanoparticles. The reaction of the carboxyl group on the D-CdSe surface with the hydroxyl group on the TiO 2 rendered QDs in direct contact with TiO 2 , thereby facilitating the electronic interaction between them.

Organic−Inorganic Nanocomposites by Placing Conjugated Polymers in Intimate Contact with Quantum Rods

“…Of the organic/inorganic hybrids, poly(3‐hexylthiopene) (P3HT) is one of the most extensively utilized CPs due to its excellent solution processability, environmental stability, high charge carrier mobility, and tailorable electrochemical properties 3, 4. CdSe quantum dots (QDs) are the most commonly investigated NCs because of their quantum‐confined nature and well‐matched energy level with P3HT 5–11…”

Crafting Semiconductor Organic−Inorganic Nanocomposites via Placing Conjugated Polymers in Intimate Contact with Nanocrystals for Hybrid Solar Cells

“…They capitalize on many advantageous attributes peculiar to conjugated polymers (CPs), such as light weight, flexibility, non‐vaccum processability, roll‐to‐roll production, low cost, and large area,3–9 in conjunction with the high electron mobility necessary for charge injection from CP, tunable optical properties, and phyical and chemical stability of inorganic nanocrystals (NCs). During the last decade significant progress have been made in colloidal synthesis10–14 and self‐assembly15–20 of NCs with well controlled shapes (dots,21–30 rods,2, 31–33 tetrapods,34–37 hyperbranched,38 wires,39–42 etc.) from a broad spectrum of semiconductor materials (e.g., metal sulfides,43–45 metal selenides,46–48 metal tellurides,49, 50 and metal oxide51), offering greatly reduced materials cost as a result of colloidal synthesis 10, 52.…”

Evaluation of biological activity of quantum dots in a microsystem

“…PL‐QD‐O‐530) as a powder (OD of 3.6 nm and maximum of fluorescence emission at 530 nm). Hydrophilic QDs, functionalized with thiol and dithiocarbamate ligands, were obtained by biphasic ligand exchange according to procedures reported previously . To obtain the QDs of desired properties, they were modified with 3‐mercaptopropionic acid (MPA) and 6‐mercaptohexanoic acid (MHA) (Fig.…”