Wire‐Like Tip‐To‐Tip Linked Assemblies of CdSe‐CdS Quantum Rods Promoted on Supramolecular Nanofibers of Hybrid Organo‐ and Hydrogels

Abstract

AbstractA variety of core‐shell CdSe‐CdS nanorods or quantum rods (QRs), both sphere (CdSe) in rod (CdS) and rod (CdSe) in rod (CdS) have been synthesized in a seeded‐growth approach using a very efficient and highly thermally stable steroidal cadmium precursor replacing the more common CdO: cadmium deoxycholate. The core‐shell QRs display high photoluminescence quantum yields (40–75%) and high molar absorption co‐efficient (ϵ=106 M−1 cm−1). Sphere‐in‐rods QRs can be co‐assembled with the organogelator diethylaminolithocholyl iodide in 1,2‐dichlorobenzene and with the hydrogelator calcium cholate in water to form hybrid gels. These organic‐inorganic hybrid soft materials are translucent and brightly red‐luminescent. The nanofibers composing the gel network act as a scaffold to support the dispersed QRs and impede their self‐aggregation. Furthermore, formation of original wire‐like assemblies of the nanorods is promoted in these gels, in particular in the hydrogel. This orientation occurs by a QR tip‐to‐tip interaction and is proposed to be driven by the amphiphilic behaviour of the QRs: laterally capped by negatively charged TGA (thioglycolic acid) ligands and un‐capped on the tips due to TGA unbinding. The combination of nanofiber‐forming hydrogelators and elongated quantum rods is promising in the perspective to form hybrid nanostructures with anisotropic optic or electronic properties.