Effect of ligands on the characteristics of (CdSe)<sub>13</sub>quantum dots

Gao, Yang; Zhou, Bo; Kang, Seung-gu; Xin, Minsi; Yang, Ping; Dai, Xing; Wang, Jianpeng; Zhou, Ruhong

doi:10.1039/c4ra03202k

Cited by 22 publications

(35 citation statements)

References 70 publications

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“…In the case of CdSe, n = 19 has also been reported to be magic. Among all the II-VI semiconductor QDs, CdSe, particularly (CdSe) 13 , is probably the most extensively studied QD [35][36][37].…”

Section: (Cdse) 13 Coating With Ligandsmentioning

confidence: 99%

“…Among many available ligands coupled to CdSe QDs [40][41][42][43][44][45], trimethyl phosphine oxide (TMPO) and its derivatives (i.e., OPMe 2 (CH 2 ) n Me, n = 0, 1-3) stand out due to their high ligand exchange capacity on the CdSe surface [46]. Zhou and coworkers [35] investigated the passivation effect of these TMPO ligands to (CdSe) 13 using the first-principle density functional theory (DFT), which has been proven as a useful methodology for the study of similar quantum systems [30][31][32][40][41][42][43][44][45][46][47][48][49][50][51]. Figure 8.1 shows the system simulated by Zhou and coworkers.…”

Section: (Cdse) 13 Coating With Ligandsmentioning

confidence: 99%

“…The passivated structures have thus been generated with TMPO on top of the toxic Cd atoms. In order to examine the capping density effect, Zhou and coworkers [35] prepared three different systems depending on the number of TMPOs (i.e., 1, 9 and 10). The ligands were first set to coordinate the unsaturated Cd atoms for cases of 1 and 9 TMPOs.…”

Section: (Cdse) 13 Coating With Ligandsmentioning

confidence: 99%

“…Atomic orbitals below the 3d/3p shell for Cd/Se atoms have been treated with the frozen core approximation, as in previous works [60]. Considering that the molecular passivation may create atypical bonds, Zhou and coworkers [35] added d polarization functions for all the C, O, and P atoms, and p polarization functions for all the H atoms by using double-ξ basis set [61] for the ligands. They also examined the symmetry effect on the molecular geometry and electronic structures by imposing the systems with C 3 symmetry identified as the most stable isomer form [37] (see more in Sect.…”

Section: (Cdse) 13 Coating With Ligandsmentioning

confidence: 99%

“…In Sect. 8.2, we will describe in detail a very recent study by Zhou and coworkers [35] using the first-principle density functional theory (DFT) to investigate the electronic structures of (CdSe) 13 passivated by OPMe 2 (CH 2 ) n Me ligands with different lengths and various numbers of branches (Me = methyl group, n = 0, 1-3). They found that the absorption peak in the ultraviolet-visible (UV-vis) spectra displays a clear blue-shift, on the scale of *100 nm, upon the binding of ligands.…”

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confidence: 99%

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Quantum Dots and Their Ligand Passivation

Zhou

2015

Modeling of Nanotoxicity

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Another major category of nanoparticles are quantum dots (QDs), which are semiconductor nanocrystals (*2-100 nm) with unique optical and electrical properties, and widely used in biomedical imaging and the electronics industries [1][2][3][4][5][6][7][8][9]. These II-VI semiconductor nanostructures (II = Zn, Cd; VI = O, S, Se, Te) display outstanding properties distinct from their bulk counterparts like broad excitation bands, large extinction coefficient, tunable emission features, bright photoluminescence, nonlinear optical properties, and high stability against photobleaching and chemicals due to the quantum nanoconfinement. These characteristic features of QDs make them amenable for solar cell components, optical sensors, and optoelectronic devices [1][2][3][4][5][6][7][8][9]. The unique fluorescence spectrum of QDs also renders them optimal fluorophores for biomedical imaging. The advantages of using QDs is that their various physicochemical factors such as particles sizes, atomic compositions are easily controllable, and this adaptability of QDs makes their applications more versatile [10][11][12][13][14][15][16]. More interestingly, inorganic QDs with comparable sizes to many biomolecules have recently been proposed as a potential platform for nanodrug carriers and/or diagnostic agents [17][18][19][20][21][22][23][24][25][26][27][28]. These advances have also raised growing concerns on their potential cytotoxicity and biocompatibility of QDs in biological environment.Recent studies suggest that QD toxicity depends on multiple factors derived from both the inherent physicochemical properties of QDs and environmental [19] QD size, charge, concentration, outer coating material, as well as oxidative, photolytic, and mechanical stability can individually or collectively determine the QD toxicity. For instance, Lovrić et al. [20] found that CdTe QDs coated with mercaptopropionic acid (MPA) and cysteamine were cytotoxic to rat pheochromocytoma cell (PC12) cultures at concentrations of 10 μg/mL. Uncoated CdTe QDs were cytotoxic at 1 μg/mL. Cytotoxicity was more pronounced with smaller positively charged QDs (2.2 ± 0.1 nm) than with larger neutrally charged QDs (5.2 ± 0.1 nm)

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