Structure−Property Correlation of CdSe Clusters Using Experimental Results and First-Principles DFT Calculations

Abstract

Structures and properties of CdSe quantum dots (clusters) up to a diameter of approximately 2 nm were investigated by combining experimental absorption, photoluminescence (PL), and X-ray diffraction (XRD) spectroscopies as well as ab initio DFT calculations. These CdSe clusters were nucleated and grown from solutions containing respective cadmium and selenium precursors following the hot-injection technique that allows one to obtain size-controlled CdSe clusters having PL efficiency up to 0.5. The DFT calculations were performed at the B3LYP/Lanl2dz level and followed by time-dependent TDDFT calculations to estimate n energy singlet transitions. On the basis of the results of these experimental and theoretical studies, an approach to determine whether the proposed cluster with a mean diameter of approximately 2 nm is more physically reasonable is discussed. It was shown that the minimum nucleus of a CdSe cluster consists of (CdSe)(3) with a six-membered ring and planar structure. No PL is observed for this structure. The formation of the next stable cluster depends on whether hexadecylamine (HDA) was used for the growth of the CdSe clusters. In the absence of HDA, the second cluster was found to be (CdSe)(6) characterized by a broad PL spectrum, while in the presence of HDA, it was found to be (CdSe)(n) (where n > or = 14) with a sharp PL spectrum.

Effect of chemical composition on luminescence of thiol-stabilized CdTe nanocrystals

“…These building blocks play a role in constructing the NCs of interest. A recent report described poorly emitting (CdSe) 13 is created in a TOPO/TOP solution, whereas strongly emitting (CdSe) 16 is created in a TOPO/TOP/HDA solution [8]. This indicates that the structure of the nucleated clusters depends on the solution.…”

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

“…[16][17][18] The research efforts in my laboratory have been focused on the development of novel nanobiodevices for biomedical applications. [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]…”