Synthesis and crystal structure of bis(morpholino dithiocarbamato) Cd(II) complex and its use as precursor for CdS quantum dots using different capping agents

ABSTRACT

Cadmium(II) morpholine dithiocarbamate complex [Cd(morphdtc)₂] was synthesized and characterized by single crystal X-ray crystallography. The molecular structure of the complex showed Cd(II) ion in a distorted 4?+?2 octahedral geometry, in which the two morpholine dithiocarbamates act as bidentate chelating and the central Cd ion bond the sulfur atoms of adjacent morpholine acting as bridging ligands to form centrosymmetric five coordinate dimeric molecules. The Cd(II) complex was thermolysed at 180°C to prepare CdS nanoparticles using three different capping agents. The pXRD patterns revealed a mixture of hexagonal and cubic crystalline phases of CdS nanocrystals. TEM images revealed semi-spherical and spherical nanoparticles, with the size range of 4.50–5.70?nm for OLM-CdS, 3.33–5.96?nm for HDA-CdS, and 3.00–5.83?nm for ODA-CdS. The particle size distribution of the CdS nanocrystallite is within the range 1.06?nm (SD?±?0.73) for OLM-CdS, 0.68?nm, (SD?±0.73) for HDA-CdS and 1.18?nm, (SD?±?0.60) for ODA-CdS. The lattice fringes showed that the particles are almost in the same environment with the interplanar of 0.32?nm for OLM-CdS, 0.34?nm for HDA-CdS, and 0.32?nm ODA-CdS. The band gaps energy were confirmed to be 1.59?eV for OLM-CdS, 1.65?eV for HDA-CdS, and 1.62?eV for ODA-CdS nanoparticles, respectively.     

Photosensitization of TiO2 nanorods with CdS quantum dots for photovoltaic devices

CdS quantum dots (QDs) coated TiO₂ nanorod arrays have been prepared via a two-step method. TiO₂ nanorod arrays were synthesized by a facile hydrothermal method, and CdS QDs were deposited on the nanorods by a sequential chemical bath deposition (S-CBD) technique. The surface morphology, structure, optical and photoelectrochemical behaviors of the core-shell nanorod array films are considered. A photocurrent of 2.5 mA/cm², an open circuit photovoltage of 1.10 V, and a conversion efficiency of 1.91% were obtained under an illumination of 100 mW/cm², when the CdS QDs deposited on TiO₂ nanorods film for about 7 cycles. The results demonstrate that the composite films are of excellence with respect to photovoltaic conversion.     

A quantum dots and superparamagnetic nanoparticle-based method for the detection of HPV DNA

Background

The recent advance in nanomaterial research field prompts the development of diagnostics of infectious diseases greatly. Many nanomaterials have been developed and applied to molecular diagnostics in labs. At present, the diagnostic test of human papillomavirus (HPV) relies exclusively on molecular test. Hereon, we report a rapid and facile quantum dots (QDs) and superparamagnetic nanoparticle-based hybridization assay for the detection of (HPV) 16 infections which combines the merits of superparamagnetic nanoparticles and QDs and wholly differs from a conventional hybridization assay at that the reaction occurs at homogeneous solution, and total time for detection is no more than 1 h.

Methods

The probes were labeled with superparamagnetic nanoparticles and QDs. Sixty cervical swab samples were used to perform a hybridization assay with these probes, and the results were compared with type-specific polymerase chain reaction (PCR) method.

Results

The statistic analysis suggests that there is no significant difference between these two methods. Furthermore, this method is much quicker and easier than the type-specific PCR method.

Conclusion

This study has successfully validated the clinical performance of our hybridization assay. The advantages in the time of detection and ease of process endow this method with great potential in clinical usage, especially mass epidemiological screening.     

Surface molecularly imprinted polymers based ZnO quantum dots as fluorescence sensors for detection of diethylhexyl phthalate with high sensitivity and selectivity

This work describes the preparation of molecularly imprinted polymers using ZnO quantum dots, which were used for the selective detection of diethylhexyl phthalate (DEHP). Methacrylic acid, ethylene glycol dimethacrylate, 2,2′‐azobis(2‐methylpropionitrile) and ZnO were used as functional monomer, crosslinker, initiator and optical material, respectively. Molecularly imprinted polymers were successfully synthesized, and the linear relationship between fluorescence intensity and amount was from 0.5 to 40 µmol L^?1 for DEHP. The coefficient of correlation was 0.9923 and the imprinting factor was 11.16. The results were above 97.50% and relative standard deviation below 3.86% for the detection of DEPH in actual water samples. This study could provide a novel method using molecularly imprinted polymers for highly selective and sensitive detection of DEHP. © 2018 Society of Chemical Industry