Free-standing single-walled carbon nanotube-CdSe quantum dots hybrid ultrathin films for flexible optoelectronic conversion devices

Efficient anchoring of nanostructured cadmium selenide on different kinds of carbon nanotubes

We report a method for the efficient anchoring of cadmium selenide (CdSe) nanoparticles on the surface of different types of multi-walled carbon nanotubes (purified, N-doped, O-doped and exfoliated). Characterization using different types of electron microscopies (SEM, STEM, and TEM), energy dispersive spectroscopy (EDS) and x-ray diffraction showed well anchored CdSe nanoparticles (NP) on the nanotube surfaces, NP shapes and sizes varied with temperature and other synthesis conditions, and formed with good yields. The method here reported does not require previous activation of the carbon nanotube surface by chemical functionalization, nor the use of organic solvents, and the reaction proceeded in aqueous solutions, making this process simpler and more environmentally friendly than others.

Enhanced Optoelectronic Conversion Efficiency of CdSe/ZnS Quantum Dot/Graphene/Silver Nanowire Hybrid Thin Films

In this study, we prepared the reduced graphene oxide (rGO)-CdSe/ZnS quantum dots (QDs) hybrid films on a three-layer scaffold that the QD layer was sandwiched between the two rGO layers. The photocurrent was induced by virtue of the facts that the rGO quenched the photoluminescence of QDs and transferred the excited energy. The quenching mechanism was attributed to the surface energy transfer, supported in our experimental results. We found that the optoelectronic conversion efficiency of the hybrid films can be significantly improved by incorporating the silver nanowires (AgNWs) into the QD layer. Upon increasing AgNW content, the photocurrent density increased from 22.1 to 80.3 μA cm(-2), reaching a near 3.6-fold enhancement compared to the pristine rGO-QD hybrid films. According to the analyses of photoluminescence spectra, shape effect, and electrochemical impedance spectra, the enhancement on the optoelectronic conversion efficiency arise mainly from the strong quenching ability of silver and the rapid electron transfer of AgNWs.

Enhanced optoelectronic performances of vertically aligned hexagonal boron nitride nanowalls-nanocrystalline diamond heterostructures

Field electron emission (FEE) properties of vertically aligned hexagonal boron nitride nanowalls (hBNNWs) grown on Si have been markedly enhanced through the use of nitrogen doped nanocrystalline diamond (nNCD) films as an interlayer. The FEE properties of hBNNWs-nNCD heterostructures show a low turn-on field of 15.2 V/μm, a high FEE current density of 1.48 mA/cm(2) and life-time up to a period of 248 min. These values are far superior to those for hBNNWs grown on Si substrates without the nNCD interlayer, which have a turn-on field of 46.6 V/μm with 0.21 mA/cm(2) FEE current density and life-time of 27 min. Cross-sectional TEM investigation reveals that the utilization of the diamond interlayer circumvented the formation of amorphous boron nitride prior to the growth of hexagonal boron nitride. Moreover, incorporation of carbon in hBNNWs improves the conductivity of hBNNWs. Such a unique combination of materials results in efficient electron transport crossing nNCD-to-hBNNWs interface and inside the hBNNWs that results in enhanced field emission of electrons. The prospective application of these materials is manifested by plasma illumination measurements with lower threshold voltage (370 V) and longer life-time, authorizing the role of hBNNWs-nNCD heterostructures in the enhancement of electron emission.

Heterogranular-Structured Diamond-Gold Nanohybrids: A New Long-Life Electronic Display Cathode

In the age of hand-held portable electronics, the need for robust, stable and long-life cathode materials has become increasingly important. Herein, a novel heterogranular-structured diamond-gold nanohybrids (HDG) as a long-term stable cathode material for field-emission (FE) display and plasma display devices is experimentally demonstrated. These hybrid materials are electrically conductive that perform as an excellent field emitters, viz. low turn-on field of 2.62 V/μm with high FE current density of 4.57 mA/cm(2) (corresponding to a applied field of 6.43 V/μm) and prominently high lifetime stability lasting for 1092 min revealing their superiority on comparison with the other commonly used field emitters such as carbon nanotubes, graphene, and zinc oxide nanorods. The process of fabrication of these HDG materials is direct and easy thereby paving way for the advancement in next generation cathode materials for high-brightness FE and plasma-based display devices.

Recent advances of resveratrol in nanostructured based delivery systems and in the management of HIV/AIDS

Resveratrol, a natural polyphenolic compound present in trees, in peanuts, in grapevines and exhibited multiple pharmacological activities. Extensive research in last two decades suggested that resveratrol possesses anti-inflammatory, anti-cancer, anti-viral, anti-amyloid, anti-arthritic and antioxidant properties. Some clinical reports have proposed that resveratrol might be a potential candidate for the prevention and/or treatment of HIV/AIDS and synergistically enhances the anti-HIV-1 activity. Resveratrol is not toxic to cells, and by itself reduces viral replication by 20% to 30%. With almost 12% of the world population suffering from HIV/AIDS including its resurgence in the developed world, better management of this global threat is highly desired. Further, various studies demonstrated several issues associated with resveratrol which account for its poor systemic bioavailability (almost zero) due to rapid and extensive first pass metabolism and existence of enterohepatic recirculation. In order to improve bioavailability and cellular uptake of resveratrol, various strategies have been adopted to date which includes resveratrol prodrug and the development of nanostructured delivery systems. Besides, nanostructured delivery systems are also known to inhibit the P-glycoprotein (P-gp) efflux, reduced metabolism by gut cytochrome P-450 enzymes, and circumnavigate the hepatic first-pass effect, facilitating absorption of drugs via intestinal lymphatic pathways. This review paper provides an updated bird's-eye view account on the publications and patents study on the recent novel approaches to deliver resveratrol in order to enhance oral bioavailability, overcome first pass metabolism and trounce enterohepatic recirculation to make resveratrol a therapeutically potent drug. Providing a relatively pithy overview, this paper thus presents recent advances of resveratrol for the treatment and prevention of HIV/AIDS.