Size-Selective Growth and Stabilization of Small CdSe Nanoparticles in Aqueous Solution

Abstract

Using cysteine and its derivatives as capping molecules, we investigated the influence of the physical structure and chemical nature of capping molecules on the selective growth and stabilization of small CdSe nanoparticles (NPs) in aqueous solution at room temperature. Our investigations revealed specific roles for each functional group of cysteine, and we could correlate this structure and nature of the capping molecules with the size, size restriction, size distribution, and stability of the NPs. For selective growth and stabilization of the NPs in aqueous solution, their capping molecules should have at least one functional group with strong nucleophilicity as well as another free, charged functional group. Capping molecules acting as a monodentate ligand were more effective than those acting as a bidentate ligand for restricting the NPs to a smaller size, whereas the former was less effective than the latter for getting a narrower NP size distribution. Capping molecules with relatively bulky spatial geometry near the ligand-NP interface resulted in the formation of NPs with poor short- and long-term stabilities, whereas those having relatively compact spatial geometry near the interface led to NPs with at least moderate short-term stability. We saw that capping molecules having relatively compact outermost spatial geometry led to NPs with excellent long-term stability, whereas those having relatively bulky outermost spatial geometry produced NPs with at most only moderate long-term stability. Our results clearly showed general trends for the possibility of selective growth of stable semiconductor NPs with particular sizes in aqueous solution.

Synthesis and luminescent properties of ultrasmall colloidal CdS nanoparticles stabilized by Cd(II) complexes with ammonia and mercaptoacetate

“…In order to produce water-soluble ultrasmall cadmium chalcogenide NPs typically either sulfur-containing stabilizers are used such as cysteine (Xia and Zhu 2008;Park et al 2010Park et al , 2011Zhou et al 2011;Pennycook et al 2012) or mercaptocarbonic acids (Rogach et al 2007;Xiao et al 2008;Chen et al 2008;Tian et al 2009;Kalasad et al 2009;Zhou et al 2011) or amine-rich dendrimers (Wu et al 2005;Fahmi et al 2009) forming strong complexes with Cd atoms on the NP surface.…”

Nano- and Microbiodevices for High-Performance Separation of Biomolecules

“…7 and 8 [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Nanobiodevices are applied to diagnosis of hypertension by the fast analysis of SNPs (single nucleotide polymorphisims) of hypertension related genes and diagnosis of lung cancer through the detection of deletion of the specific sequence for the lung cancer related genes.…”

Nanobiodevice-based Single Biomolecule Analysis, Single-Cell Analysis, and in vivo Imaging for Cancer Diagnosis, Cancer Theranostics, and iPS Cell-based Regenerative Medicine

“…[1][2][3][4][5][6][7] In this review article, we mainly overview our research activities, including nanobiodevices for single-cell analysis, [20][21][22][23][24][25] single biomolecule analysis, 19,[26][27][28][29]41,46,50,[54][55][56][57][58] biomarker detections, 23,[30][31][32][33]39,[47][48][49] cancer theranostics, and iPS cell in vivo imaging. [20][21][22][23][24][25][34][35][36][37][38]40,[42][43][44][45]…”