ABSTRACT
A highly flexible and cost-effective copper tape decorated with silver nanoparticles (Cu-TAg) has been developed for surface-enhanced Raman spectroscopy (SERS) sensing of multi-hazardous environmental pollutants. Highly ordered and spherical-shaped silver nanoarrays have been fabricated using a low-cost thermal evaporation method. The structural, morphological, and optical properties of Cu-TAg sensors have been studied and correlated to the corresponding SERS performances. The size of nanoparticles has been successively tuned by varying the deposition time from 5 to 25 s. The nanoparticle sizes were enhanced with an increase in the evaporation time. SERS investigations have revealed that the sensing potential is subsequently improved with an increase in deposition time up to 10 s and then deteriorates with further increase in Ag deposition. The highest SERS activity was acquired for an optimum size of ~ 37 nm; further simulation studies confirmed this observation. Moreover, Cu-TAg sensors exhibited high sensitivity, reproducibility, and recycling characteristics to be used as excellent chemo-sensors. The lower detection limit estimation revealed that it can sense even in the pico-molar range for sensing of rhodamine 6G and methylene blue. The estimated enhancement factor of the sensor is found to be 9.4 × 107. Molecular-specific sensing of a wide range of pollutants such as rhodamine 6G, alizarin red, methylene blue, butylated hydroxy anisole, and penicillin-streptomycin is demonstrated with high efficiencies for micromolar spiked samples. Copper tape functionalized with Ag arrays thus demonstrated to be a promising candidate for low-cost and reusable chemo-sensors for environmental remediation applications.
ABSTRACT
In this study, nanomaterials (ZnO and CaO) and ZnO-CaO nanocomposites (Zn25Ca75O; Zn50Ca50O; Zn75Ca25O) were prepared using co-precipitation method and physico-chemically characterized by XRD, FT-IR, and SEM with EDAX analysis. The XRD pattern of ZnO nanomaterials exhibits hexagonal wurtzite structure and CaO nanomaterials exhibit face-centered cubic (FCC) structure whereas nanocomposites (Zn75Ca25O, Zn50Ca50O, Zn25Ca75O) exhibit both hexagonal phase of ZnO and cubic phase of CaO. The SEM images of ZnO-CaO nanocomposites show the well-distributed clusters composed of ZnO and CaO nanoparticles with most of the particles are spherical and some of the particles are rod- and cubic-like morphology. Furthermore, nanomaterials and nanocomposites were used as nano-seed priming agents to assess the seed germination and seedling growth parameters of mung beans. Among the nano-seed priming agents, 500 ppm concentration of the nanocomposite (Zn50Ca50O) showed significant enhancement of germination (100%) and shoot length (11.7 cm), root length (8.9 cm), and vigor index (1910) than other nanomaterials and nanocomposites.
Subject(s)
Nanocomposites , Nanoparticles , Vigna , Zinc Oxide , Nanocomposites/chemistry , Nanoparticles/chemistry , Spectroscopy, Fourier Transform Infrared , Zinc Oxide/chemistryABSTRACT
As proficient photovoltaic devices, dye-sensitized solar cells (DSSCs) have received considerable consideration in recent years. In order to accomplish advanced solar-to-electricity efficiency and increase long-term functioning stability, improvements in the configuration structure of DSSCs are essential, as is an understanding of their elementary principles. This work discusses the application of different semiconductor constituents designed for effective DSSCs. The main parameters crucial to fabrication of DSSC electrodes in nano-porous semiconductor structures are high surface area and large pore size. Different inorganic semiconductor materials are used to load sensitizer dyes, which absorb a lot of light and induce high photocurrent for efficient DSSCs. The first section of the review covers energy sources, photovoltaics, and the benefits of solar cells in daily life, while the second part includes the various types of semiconductors applied in DSSC applications. The final section provides a brief review of future perspectives for DSSCs and a survey of semiconductor materials proposed for solar cell applications.
