There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Review on the improvement of the photocatalytic and antibacterial activities of ZnO

Yu Bai,†,‡ Ivań Mora-Sero,́ Filippo De Angelis, Juan Bisquert, and Peng Wang*,† †State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China ‡Institute of Chemistry and Energy Material Innovation, Academy of Fundamental Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080, China Photovoltaic and Optoelectronic Devices Group, Departament de Física, Universitat Jaume I, 12071 Castello,́ Spain Istituto CNR di Scienze e Tecnologie Molecolari, c/o Dipartimento di Chimica, Universita ̀ di Perugia, via Elce di Sotto 8, I-06123 Perugia, Italy

Titanium Dioxide Nanomaterials for Photovoltaic Applications

Rapid progress in identifying biomarkers that are hallmarks of disease has increased demand for high-performance detection technologies. Implementation of electrochemical methods in clinical analysis may provide an effective answer to the growing need for rapid, specific, inexpensive, and fully automated means of biomarker analysis. This Review summarizes advances from the past 5 years in the development of electrochemical sensors for clinically relevant biomolecules, including small molecules, nucleic acids, and proteins. Various sensing strategies are assessed according to their potential for reaching relevant limits of sensitivity, specificity, and degrees of multiplexing. Furthermore, we address the remaining challenges and opportunities to integrate electrochemical sensing platforms into point-of-care solutions.

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Electrochemical Methods for the Analysis of Clinically Relevant Biomolecules

This review captures the synthesis, assembly, properties, and applications of copper chalcogenide NCs, which have achieved significant research interest in the last decade due to their compositional and structural versatility. The outstanding functional properties of these materials stems from the relationship between their band structure and defect concentration, including charge carrier concentration and electronic conductivity character, which consequently affects their optoelectronic, optical, and plasmonic properties. This, combined with several metastable crystal phases and stoichiometries and the low energy of formation of defects, makes the reproducible synthesis of these materials, with tunable parameters, remarkable. Further to this, the review captures the progress of the hierarchical assembly of these NCs, which bridges the link between their discrete and collective properties. Their ubiquitous application set has cross-cut energy conversion (photovoltaics, photocatalysis, thermoelectrics), en...

Compound Copper Chalcogenide Nanocrystals

Pd doped WO3 films prepared by sol–gel process for hydrogen sensing

The aim of this study was to assess the effects of two different types of SiO2 nanoparticles (N and M series) with different ratios on the workability and compressive strength of developed binary blended concretes cured in water and lime solution as two different curing media. N and M series SiO2 nanoparticles with an average size of 15 nm were used as obtained from the suppliers. Fresh and hardened concretes incorporating 0.5%, 1.0%, 1.5% and 2.0% of N and 2% of M series nanoparticles with constant water to binder ratio and aggregate content were made and tested. Fresh mixtures were tested for workability and hardened concretes were tested for compressive strength at 7, 28 and 90 days of curing. Fresh concrete test results showed that the workability of binary blends was reduced in the presence of both types of SiO2 nanoparticles. Hardened concrete test results revealed that the optimal replacement level of cement by N series of SiO2 nanoparticles for producing concrete with considerably improved strength was set at 1.0 wt.% after curing in water. However, the ultimate strengths of binary blended concretes were gained at 2.0 wt.% replacement of cement by both series after curing in lime solution. It is concluded that SiO2 nanoparticles play significant roles in mechanical properties of concrete by formation of additional calcium silicate hydrate gel during treatment, which played an important role in raising highly the compressive strength of binary blends. The current study sheds light on the implications of nanotechnology in nano-engineering of concrete.

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Investigating the effects of using different types of SiO2 nanoparticles on the mechanical properties of binary blended concrete

Surface treatments of TiO2 nanostructure in semiconductor quantum dot sensitized solar cells (QDSCs) aimed to increase the photovoltaic conversion efficiencies of the solar cells are analyzed. A fluorine treatment, with NH4F or HF, on the TiO2 electrodes leads to a general increase of QDSCs performance in a range of QDSCs using different light absorbing materials: CdS, CdSe, and PbS/CdS. In contrast, no significant effect on QDSC performance has been observed after a TiCl4 treatment conventionally used for high performance dye sensitized solar cells (DSCs). Surface and photoelectrochemical characterization of treated electrodes and full solar cells was carried out by means of X-ray photoelectron spectroscopy (XPS), impedance spectroscopy (IS), and applied bias voltage decay (ABVD), to understand the origin of the beneficial effect of fluorine. It was found that the origin of the enhancement is different depending on the semiconductor material (CdS, CdSe, and PbS/CdS). For CdS and CdSe, the recombination o...

Fluorine Treatment of TiO2 for Enhancing Quantum Dot Sensitized Solar Cell Performance

Highly sensitive nonenzymetic glucose sensing platform based on MOF-derived NiCo LDH nanosheets/graphene nanoribbons composite

In the present study, a 3D porous graphene-carbon nanotube (G-CNT) network is successfully constructed on the surface of glassy carbon electrode (GCE) by electrochemical co-deposition from a concentrated graphene dispersion. The large accessible surface area provided by the interpenetrated graphene backbone in one hand and the enhanced electrical conductivity of the 3D network by incorporating CNTs on the other hand, dramatically improved the electrochemical performance of GCE in determination of Methotrexate (MTX) as an important electroactive drug compound. Under the optimum conditions, the electrode modification led to a significant increase in the anodic peak current (∼25 times) along with a considerable shift in the peak potential (∼111 mV). Voltammetric investigations revealed that the proposed method can determine MTX in a wide dynamic linear range with a low detection limit of 70 nM. Moreover, good sensitivity and high accuracy of the prepared modified electrode in voltammetric detections of MTX, which was further confirmed by UV–vis spectroccopy and HPLC methods, make it very suitable for accurate determinations of MTX in pharmaceutical formulations (commercial tablets) and clinical preparations (blood serum) with excellent recoveries.

Azam Iraji zad

Papers

Pd doped WO3 films prepared by sol–gel process for hydrogen sensing

Investigating the effects of using different types of SiO2 nanoparticles on the mechanical properties of binary blended concrete

Fluorine Treatment of TiO2 for Enhancing Quantum Dot Sensitized Solar Cell Performance

Highly sensitive nonenzymetic glucose sensing platform based on MOF-derived NiCo LDH nanosheets/graphene nanoribbons composite

Glassy carbon electrode modified with 3D graphene–carbon nanotube network for sensitive electrochemical determination of methotrexate