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Plasmonic coatings can absorb electromagnetic radiation from visible to far-infrared spectrum for the better performance of solar panels and energy saving smart windows. For these applications, it is important for these coatings to be as thin as possible and grown at lower temperatures on arbitrary substrates like glass, silicon, or flexible polymers. Here, we tune and investigate the plasmonic resonance of titanium nitride thin films in lower thicknesses regime varying from ~ 20 to 60 nm. High-quality crystalline thin films of route-mean-square roughness less than ~ 0.5 nm were grown on a glass substrate at temperature of ~ 200 °C with bias voltage of - 60 V using cathodic vacuum arc deposition. A local surface-enhanced-plasmonic-resonance was observed between 400 and 500 nm, which further shows a blueshift in plasmonic frequency in thicker films due to the increase in the carrier mobility. These results were combined with finite-difference-time-domain numerical analysis to understand the role of thicknesses and stoichiometry on the broadening of electromagnetic absorption.
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[This corrects the article DOI: 10.1039/D3RA00752A.].
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Polygonatum verticillatum Linn. is an endangered medicinal herb from Himalayas whose rhizomes have recently been used to curate symptoms of COVID-19. During present investigation, a gene bank of P. verticillatum was established at High Altitude Herbal Garden of Forest Research Institute, Dehradun at Chakrata, at 2600 m amsl with germplasm collected from different states and union territory of India including Himachal Pradesh, Sikkim, Uttarakhand and Jammu and Kashmir covering a wide range of geographical locations from an altitude of 1800 to 3600 m amsl. Genotyping by sequencing was applied to a set of 66 accessions of P. verticillatum to identify genome-wide high quality single nucleotide polymorphisms (SNPs) for analysis of genetic diversity. Neighbour-joining tree created from the distance matrix data grouped the genotypes into five distinct clusters. The results of principal coordinate analysis and Cluster analysis overlapped to identify Narkanda, Shimla (Himachal Pradesh) and Sunil village, Chamoli (Uttarakhand) as the regions with undisturbed, highly diverse natural populations of P. verticillatum. The species displayed little congruence in terms of genetic similarities with altitudinal range. This investigation is first of its kind on generation and utilization of SNPs to analyse genetic diversity in P. verticillatum with a very vivid sample collection across the entire Himalayan range in India. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03654-4.
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We report an infrared (IR) sensitive mixed phase of V7O16 and V2O5 thin films, grown by cathodic vacuum arc-deposition on glass substrates at relatively low temperatures. We have found that the mixed phase of V7O16 and V2O5 can be stabilized by post-annealing of amorphous VxOy between 300-400 °C, which gets fully converted into V2O5 after annealing at higher temperatures â¼450 °C. The local conversion from VxOy to V2O5 has also been demonstrated by applying different laser powers in Raman spectroscopy measurements. The optical transmission of these films increases as the content of V2O5 increases but the electrical conductivity and the optical bandgap decrease. These results are explained by the role of defects (oxygen vacancies) through the photoluminescence (PL) and time-resolved photoluminescence (TRPL) measurements. The IR sensitivity of the mixed phase is explained by the plasmonic absorption by the V7O16 degenerate semiconductor.
RESUMEN
In solar photocatalysis, light utilization and recycling of powder from reaction solution are the main obstructions that hinder the photocatalytic efficacy of any photocatalyst. In this respect, a floatable system is effective for efficient solar photocatalysis by light utilization. Due to the maximum solar light absorption property, floating nanocomposite photocatalyst is an appealing substitute for effective wastewater treatment. Floating photocatalysts are a non-oxygenated and non-stirred solution that is a good light harvester, stable, non-toxic, biodegradable, naturally abundant in nature. They also have low density, a simple preparation process, no need to stir, and high porosity. Due to these characteristics, floating photocatalysts are widely favored and ideal candidates for practical environmental remediation. Several researchers have come up with new and innovative ways for immobilizing capable photocatalyst on a floatable substrate to produce floating nanocomposite photocatalytic material. In recent decades, g-C3N4-based floating photocatalysts have gained a lot of attention as g-C3N4 is a visible light active photocatalyst with unique and exceptional properties. It also has good photocatalytic activity in waste water treatment and environmental remediation. Many previous reports have studied the logical design and manufacturing method for heterojunction floating photocatalysts and immobilized floating photocatalysts. Based on those studies, we have focused on the g-C3N4 based immobilized and non-immobilized floating photocatalysts for pollutant degradation. We have also categorized immobilized floating photocatalyst based on several lightweight substrates such as expanded perlite and glass microbead. In addition, future challenges have been discussed to maximize solar light absorption and to improve the efficiency of broadband response floating photocatalysts. Floating photocatalysis is an advanced technique in energy conversion and environmental remediation thus requires special consideration.
