Noncovalent Attachment of PbS Quantum Dots to Single- and Multiwalled Carbon Nanotubes

Abstract

Attachment of PbS quantum dots (QD) to single-walled carbon nanotubes (SWNT) and multiwalled carbon nanotubes (MWCNT) is described; wherein commercially obtained PbS-QD of size 2.7 nm, stabilized by oleic acid, are added to a suspension of single- or multiwalled carbon nanotubes (CNT) prefunctionalized noncovalently with 1,2-benzenedimethanethiol (1,2-BDMT) in ethanol. The aromatic part of 1,2-BDMT attaches to the CNT byπ-πstacking interactions, noncovalently functionalizing the CNT. The thiol part of the 1,2-BDMT on the functionalized CNT replaces oleic acid on the surface of the QD facilitating the noncovalent attachment of the QD to the CNT. The composites were characterized by TEM and FTIR spectroscopy. Quenching of NIR fluorescence of the PbS-QD on attachment to the carbon nanotubes (CNT) was observed, indicating FRET from the QD to the CNT.

Recent Developments in Quantum Dots/CNT Co-Sensitized Organic Solar Cells

“…Nevertheless, when simple physical mixing is applied long deposition times, low photocurrents due to the isolating effect of the ligands and inefficient deposition of QDs on CNTs backbone is the minimum shortcomings of this approach. Das et al, [133] proposed a method for the attachment of commercially obtained oleic acid stabilized monodispersed PbS QD with the size of 2.7 nm onto the surface of CNT prefunctionalized by an aromatic dithiol (1,2-BDMT). They believed that the aromatic part of 1,2-BDMT attaches to the CNT by π-π stacking interactions and the thiol part replaces oleic acid on the surface of QDs, leading to the non-covalent attachment of the QD to the CNT.…”

“…However, in this approach controlled deposition of QDs is complicated and agglomeration is inevitable. Consequently, covalent functionalization of CNT [133], QDs [16] or both of these two nanomaterial's [22] has been studied. Cho et al [134] have shown that by thiol covalent modification of SWNT, a large number of PbSe QDs are attached on the surface of CNT.…”

Functional Quantum Dots for Promising Cancer Diagnosis and Therapy

“…Conjunction: Conjunction, which can be grouped into two general strategies: noncovalent coupling [38] and covalent coupling [39,40], is a common fabrication method. Some functional QDs have been fabricated by noncovalent coupling such as electrostatic interactions [20] or π-π stacking interactions [31].…”

“…To fabricate the functional QDs, other intermediate molecules including 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and/ or N-hydroxysuccinimide (NHS) have been involved [6,11,38]. QDs were first covalently coupled with aptamer specific for mutated MUC1 mucin overexpressed in ovarian carcinoma cells, followed by doxorubicin covalently coupled with QDs -MUC1 aptamer conjugates by EDC and NHS [6].…”

Hybrid systems based on metal oxide and nanocarbons: electronic properties and applications for photocatalysis

“…[Vilatela and Eder 2012;Eder 2010;Shearer et al 2014] In the ex-situ route, also known as the building block approach, the two components are synthesised separately and then attached using covalent, non-covalent or electrostatic interactions (Figure 2.4). This strategy has been used to successfully link nanoparticles [Yeh et al 2009], quantum dots [Das et al 2014], polymers [Gegenhuber et al 2015] and biomolecules, especially proteins [Kuila et al 2010]. In contrast, in the in-situ route, one component of the hybrid is synthesised in presence of the other or sometimes both are synthesised at the same time.…”