Rohit L. Vekariya

Synthesis and characterization of double –SO3H functionalized Brönsted acidic hydrogensulfate ionic liquid confined with silica through sol-gel method

Abstract Imidazolium-based metal and halogen-free Brönsted acidic ionic liquid (BAIL) (3,3′-(hexane-1,6-diyl)bis(2-methyl-1-(3-sulfopropyl)-1H-benzimidazolium) hydrogensulfate [HbMBIM-PS][HSO4] was synthesized. The physicochemical properties of this BAIL were investigated using a variety of different analytical and spectroscopic techniques such as 1H and13C-NMR, FT-IR, mass, UV–vis and TGA spectra. A porous silica matrix has been synthesized using BAIL and tetraethoxysilane (TEOS) as silica source by nonhydrolytic sol–gel method. The properties of IL confined silica gel matrix have been studied using FTIR, TGA, SEM, N2-sorption measurement (BET characterization for determining pore parameters), and NH3-TPD techniques. From the N2-sorption measurement, it has been found that BET surface area decreased while pore volume, average pore size and porosity decreased. The thermal stability of the IL has been found to increase upon confinement in silica gel matrix. The results suggested that IL had been successfully confined on silica gel. This IL confined silica gel catalyst is environment friendly and useful for alkane isomerization and esterification reactions.

Effects of cationic head groups of ionic liquid on micellization in aqueous solution of PEO-PPO-PEO triblock copolymer

ABSTRACT The interaction of ionic liquids (ILs) with non-ionic triblock copolymer, Pluronic® P123 in aqueous solutions has been investigated using DLS, surface tension, and viscosity measurements. The addition of ILs increased the Critical Micelle Concentration (CMC) of P123, which appears to be logistic. As the added IL enhances the solubility of PPO moiety (and PEO), which makes them to behave like a more hydrophilic block copolymer that would be micellized at high copolymer concentration. The DLS data is in good agreement to the results observed from surface tension measurements. Viscosity results show the propensity in micellar size reduction upon addition of ILs, and hence, intrinsic viscosity decreases as compared to pure P123 aqueous solution. The results are studied and discussed as a function of cationic head groups of N-octyl-pyridinium/imidazolium chloride based ILs. GRAPHICAL ABSTRACT

Fabrication and characterization of next generation nano-structured organo-lead halide-based perovskite solar cell

AbstractGeneration of alternative source of energy is one of the talks of the present decade. In the present work, the focus has been given to produce energy from perovskite-based solar cells. For this purpose, a unique and novel nano-structured perovskite material ethyl ammonium lead chloride (C2H5NH3+PbCl3−) was prepared through a novel co-precipitation route using ethyl amine (C2H5NH2) and hydrochloric acid as the starting precursors with aqueous solution of Pb(CH3COO)23H2O. Finally acetic acid was added in the solution, and this solution was allowed to concentrate and cooled down at room temperature. Then the synthesized material was deposited over TiO2 film in order to fabricate the solar cell. Systematic study using XRD, SEM, UV, and photo conversion were conducted to properly analyze the structural, optical, and electrical properties of device. In the presence of light, this perovskite-based solar cell has shown energy conversion efficiency (η) of around 5.2% which is appreciably good. This result has depicted that this material is promising material for fabrication of highly efficient solar cells. This technology can be applied in industrial scale as substitute of the conventional energy in the future. Graphical abstractᅟ

Dependency of Anion and Chain Length of Imidazolium Based Ionic Liquid on Micellization of the Block Copolymer F127 in Aqueous Solution: An Experimental Deep Insight

The non-ionic triblock copolymer, Pluronic® F127, has been selected to observe its interaction with ionic liquids (ILs) in aqueous solutions by using DLS, surface tension, and viscosity measurements. The Critical Micelle Concentration (CMC) of F127 increased with the addition of ILs, which appeared logical since it increases the solubility of PPO (and PEO) moiety, making it behaves more like a hydrophilic block copolymer that is micellized at a higher copolymer concentration. The results from DLS data showed good agreement with those obtained from the surface tension measurements. Upon the addition of ILs, the tendency in micellar size reduction was demonstrated by viscosity results, and therefore, intrinsic viscosity decreased compared to pure F127 in aqueous solution. The results were discussed as a function of alkyl chain length and anions of imidazolium based ILs.

Reduction of micellar size of PEO−PPO−PEO triblock copolymer in presence of ionic liquid in aqueous solutions: A SANS study

ABSTRACT The interaction of ionic liquids (ILs) with non-ionic triblock copolymer, Pluronic® P123, in aqueous solutions has been investigated using Small Angle Neutron Scattering (SANS) measurements. The micellar structural parameters are obtained by fitting the SANS scattering data with model composed of core-shell form factor and a hard sphere structure factor of interaction, as a function of cationic head group of ILs. With the addition of ILs, a decrease in the micellar core, aggregation number, and hard sphere radius of P123 micelles was noticed. The results are discussed and explained as a function of cationic head groups of N-octylpyridinium/imidazolium chloride. GRAPHICAL ABSTRACT

An overview of engineered porous material for energy applications: a mini-review

The ordered porous materials, developed using various templating materials, have generated huge interest among the electrochemist community due to their plenty of unique properties and functionalities that can be effectively applied in optoelectronic devices. Mesoporous materials possess excellent opportunities in energy storage and energy conversion applications due to their extraordinarily high surface area and large pore size. These properties may enhance the performance of porous materials in terms of lifetime and stability, energy and power density. In this review, we have tried to club the fields of optoelectronics and mesoporous materials. Also, we have summarised the primary methods for preparing mesoporous materials using various templates and described their applications as electrodes and catalysts in fuel cells, solar fuel production, dye-sensitised solar cells, perovskite, supercapacitors and rechargeable batteries. Finally, we have highlighted the research and development challenges of mesoporous materials those need to be overcome to enhance their contribution in renewable energy applications.

Pyridinium-clubbed dicationic ionic liquid electrolytes for efficient next-generation photo harvesting

We have developed a new series of pyridinium based dicationic ionic liquids (DCILs) having excellent thermal stability and good ionic conductivity. The effectiveness of these DCIL based electrolytes in photovoltaic devices and the effect of different anions (e.g. iodine, bromide, and thiocyanate) versus the device performance are studied by cyclic voltammetry (CV), current–voltage (I–V) characteristics and electrochemical impedance spectroscopy (EIS). The electrolyte 2PrSCN based device C exhibited the highest photo conversion efficiency (PCE) of 5.23% under 1 sun (100 mW cm−2) illumination of light. We have also analyzed the influence of various anions in metal-free dye-sensitized TiO2 and the DCIL interface using the EIS technique. Device C based on 2PrSCN shows excellent long-term stability, maintaining <95% of the initial efficiency after 500 h.

Fabrication of D–π–A sensitizers based on different donors substituted with a dihydropyrrolo[3,4-c]pyrrole-1,4-dione bridge for DSSCs: influence of the CDCA co-absorbent

The effect of co-absorbance on the performance of DSSC devices with a new design of dimer sensitizers possessing a 2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (DPP) bridge and various donor groups (carbazole, diphenyl amine, indole) is reported in the present work. The co-absorbent (CDCA = chenodeoxycholic acid) was inserted into the sensitizers and the photovoltaic performance was studied. The co-absorbent had a significant effect on Jsc, Voc and the efficiency. Without incorporation of the co-absorbent, a higher efficiency of around 4.40% is exhibited (Jsc = 9.91 mA cm−2 and Voc = 0.678 V) by the R3 device, while after adding the co-absorbent, we have achieved an efficiency of around 4.44% (Jsc = 10.3 mA cm−2 and Voc = 0.693 V). Structure optimization and energy level calculations were carried out by density functional theory (DFT) with different donor substituents and DPP bridge based sensitizers. The co-absorbent and sensitizer based DSSCs were also characterised by impedance spectroscopy and incident photon to current conversion efficiency measurements.

Marine Natural Product Bis-indole Alkaloid Caulerpin: Chemistry and Biology

Marine bis-indole alkaloids comprise a large and increasingly growing class of secondary metabolites, and continue to deliver a great variety of structural templates for diverse biological targets. The alkaloids derived from marine resources play a crucial role in medicinal chemistry and as chemical agents. In particular, bis-indole alkaloid caulerpin which has been isolated from marine green algae Caulerpa and a red algae Chondria armata at various places around the world, was tested for several therapeutic potentials such as anti-diabetic, antinociceptive, anti-inflammatory, anti-tumor, anti- larvicidal, anti-herpes, anti-tubercular, anti-microbial and immunostimulating activities as well as a means of other chemical agents. Herein, we summarized the discovery and isolation of caulerpin, and its potential medicinal and chemical applications in chronological order with various aspects. Additionally, synthesis of caulerpin and its functional analogues have also been reviewed.