A. Nemati,
Volume 17, Issue 2 (6-2020)
Abstract
Synthesis of materials at nano scale is one of the main challenges in nanotechnology for different applications such as semiconductor, superconductors, electro-optics devices, advanced ceramics, refractories, diagnostic imaging and drug delivery. Semiconductors nanocrystals, known as “Quantum Dots”, have emerged as new generation of nanomaterials due to their unique optical, electrical and electrochemical properties, for variety of applications such as contrasts agents, fluorescent labels, localized targeted drug delivery and new generation of biosensors. Quantum dots advantages over traditional nanomaterials are due to quantum confinement effect, which bring broad absorption spectra, superior brightness and durability for different applications. The most important factor in developing nano carriers for biological applications is the toxicity, so recent researches have been focused on heavy metal-free formulations and nontoxic ceramics and polymers. So, one of the main goals in this paper is to explicate efficiencies and deficiencies of recent advances in quantum dot based formulations with the least toxicity for bioimaging, therapeutic and drug delivery applications. Another area of quantum dot’s application is the determination of dopamine (DA). Due to basic role of DA in some diseases like Parkinson and Schizophrenia, its determination is important and thus, it is desirable to develop new, simple and rapid analytical methods for the determination of DA with high selectivity and sensitivity, especially for diagnostic applications. Recently, developments in nanotechnology and preparations of semiconductors quantum dots cause open a new field in photo-electrochemical methods based on semiconductors quantum dots for determination of DA. In this review, an attempt was made to elaborate the mentioned goals of the paper in details.
Saba Payrazm, Saeid Baghshahi, Zahra Sadeghian, Amirtaymour Aliabadizadeh,
Volume 19, Issue 3 (9-2022)
Abstract
In this research, zinc oxide quantum dots and graphene nanocomposites were synthesized via two different methods; In the first (direct) method, ZnO-graphene Nanocomposites were made mixing the synthesized zinc oxide and graphene. In the second (indirect) method, zinc nitrate, graphene, and sodium hydroxide were used to made ZnO-graphene Nanocomposites. XRD, FTIR and Raman spectroscopy analyses were used for phase and structural evaluations. The morphology of the nanocomposites w::as char::acterized by SEM. The specific surface area and porosity of the samples were characterized by BET analysis. The optical properties of the samples were investigated by photoluminescence and ultraviolet-visible spectroscopy analyses. Results showed that using graphene, increased the photoluminescence property and shifted the photoluminescence spectrum of the composites towards the visible light spectrum. The photoluminescence of the synthesized graphene-zinc oxide composite, in the visible light region, was closer to white light than that of pure zinc oxide. According to the results of BET test, the nanocomposite synthesized by direct method had a higher surface area (25.7 m2.g-1) and a higher porosity (0.32 cm3.g-1) than the nanocomposite synthesized by the indirect method with a specific surface area of (16.5 m2.g-1) and a porosity of 0.23 cm3.g-1).
