RESUMEN
Silicon nanowires (NWs) are appealing building blocks for low-cost novel concept devices with improved performances. In this research paper, we realized a hybrid platform combining an array of vertically oriented Si NWs with different types of bucky gels, obtained from carbon nanotubes (CNT) dispersed into an ionic liquid (IL) matrix. Three types of CNT bucky gels were obtained from imidazolium-based ionic liquids (BMIM-I, BIMI-BF4, and BMIM-Tf2N) and semiconductive CNTs, whose structural and optical responses to the hybrid platforms were analyzed and compared. We investigated the electrical response of the IL-CNT/NW hybrid junctions in dark and under illumination for each platform and its correlation to the ionic liquid characteristics and charge mobility. The reported results confirm the attractiveness of such IL-CNT/NW hybrid platforms as novel light-responsive materials for photovoltaic applications. In particular, our best performing cell reported a short-circuit current density of 5.6 mA/cm2 and an open-circuit voltage of 0.53 V.
RESUMEN
A deep eutectic solvent based magnetic nanofluid was coupled with stir bar sorptive dispersive microextraction as a hyphenated sample preparation technique. The neodymium core magnetic stir bar was coated physically with nanofluid of magnetic carbon nanotube nanocomposites and deep eutectic solvents. The prepared nanofluid has magnetic and strong sorbing properties and is compatible with gas chromatography. In this nanofluid, the deep eutectic solvent acts simultaneously as both carrier and stabilizer for magnetic nanotubes. The predominant experimental variables affecting the extraction efficiency of nitroaromatic compounds were evaluated. Under the optimized conditions, the limit of detection and enrichment factor were in the range of 0.2-4.9 ng/L and 852-1480, respectively. The relative standard deviations were between 5.6 and 10.2% (n = 6). Method validation was performed by both spiking-recovery method and comparison of results with other methods. Finally, the proposed method was successfully applied for the extraction and pre-concentration of nitroaromatic explosives in water samples, followed by determination by gas chromatography with micro-electron capture detection.
RESUMEN
Novel deep eutectic solvent (DES) magnetic bucky gels (MBG) were formed by choline chloride/urea deep eutectic solvent and magnetic multi-walled carbon nanotube nanocomposite (MMWCNT) and were used in developing dispersive solid-phase extraction (dSPE) method. The hydrophilic DES based MBGs were developed with the features of magnetic susceptibility to permit fast injection of sorbent into the aqueous sample, rapid retrieval of the sorbent, high dispersion of MWCNT in water and compatibility with GC. In this work we investigated the application of DESs as a new class of carriers for CNT based nanofluids. In this gel DES acts simultaneously as a carrier and stabilizer for MMWCNT nanoparticles. By combining the MWCNT nanocomposite and DES, a highly stable (stability against sedimentation) viscous magnetic bucky gel or soft material was prepared without any additional stabilizer. This gel possesses fluidity, stability, magnetic properties and the unique strong sorbing properties of MWCNT simultaneously. We used the advantages of this magnetic DES based soft material in developing a new DES magnetic bucky gel based dispersive solid phase extraction. By coupling this method with GC- micro ECD and using large-volume-injection technique we achieved low LOD values which is a necessity in the ultra trace analysis of organochlorine pesticides (OCPs) in environmental water samples. Under the optimized conditions, the enrichment factors were in the range of 270-340. The limits of detection were between 0.04 and 0.27ng/L and the relative standard deviations were <10%. This method was successfully used for the determination of OCPs with good reproducibility and recovery.