Search

In this work, different concentrations of lithium iodide (LiI) have been added to the gel polymer electrolyte (GPE) containing PEO and PVA in equal ratio, tetrabutylammonium iodide (TBAI), ethylene carbonate (EC), dimethyl sulfoxide (DMSO) and iodine crystals (I2). The effect of introducing lithium iodide (LiI) into PEO-PVA blended GPE system having TBAI has been investigated in terms of optical, electrical, thermal and electrochemical characteristics. Fourier transform infrared (FTIR) spectroscopy has been carried out to study the interaction of LiI with the GPEs. The GPE without LiI showed the highest conductivity of 5.50 mS cm−1 at room temperature. With the incorporation of LiI, decrement in conductivity was observed. Dye-sensitized solar cells (DSSCs) with configuration FTO/TiO2/N3-dye/GPE/Pt/FTO have been fabricated and tested under white light of intensity 100 mW cm−2. The DSSC made of GPE with 1.34 wt% LiI exhibited highest efficiency, η of 6.26%.

A new gel electrolyte comprising methylcellulose (MC), LiBOB and succinonitrile (SN) has been prepared with dimethyl sulfoxide (DMSO) as solvent. The electrolyte with composition 8.73 wt % MC–2.92 wt % LiBOB–1.01 wt % SN–87.34 wt % DMSO exhibits the highest conductivity of 1.18 mS cm-1 at 25 °C. On partially substituting LiBOB with TMAI, the sample designated as TMAI 95 has the highest conducting composition of 8.70 wt % MC–0.14 wt % LiBOB–1.01 wt % SN–2.77 wt % TMAI–0.35 wt % I2–87.03 wt % DMSO. The conductivity is 1.96 mS cm−1. This sample is used to fabricate a dye sensitized photovoltaic cell that converts photons to electricity at an efficiency of 3.46%. The conductivity of this sample has been enhanced to 3.08 mS cm−1 on addition of 1.0 wt % butyl-methyl immidazolium iodide (BMII) ionic liquid and the efficiency of the cell fabricated is 4.63%. Total replacement of LiBOB component in the electrolyte with the same amount of LiI results in a conductivity increase of ∼23.5% and the DSSC exhibits a 5.72% efficiency.

In this work, poly (methyl methacrylate), PMMA based gel polymer electrolytes (GPEs) have been studied. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was selected as lithium-ion donor and tetraethylene glycol dimethyl ether (TEGDME) as a solvent. The highest conducting sample was obtained at 25 wt% LiTFSI with ionic conductivity value of 2.80 mS cm−1. The dielectric constant of GPEs sample follows the conductivity trend. The percentage of free ions is observed to increase up to electrolyte containing 25 wt% LiTFSI salt. Beyond that, the free ions percentage decreased. Lithium-ion transference number for the highest conducting sample is 0.47. The highest ionic conducting sample show good electrode-electrolyte interfacial stability and is suggested suitable in lithium-oxygen batteries. The charge and discharge capacities in the first cycle were 0.87 and 1.23 mAh cm−2, respectively. Formation of Li2O2 can be observed by XRD pattern of the air cathode during the discharge.

This study focused on designing an experimental model in order to evaluate the influence of operative extraction parameters employed for anthocyanin extraction from Ixora siamensis on CIE color measurements (a*, b* and color saturation). Extractions were conducted at temperatures of 30, 55 and 80°C, soaking time of 60, 120 and 180 min using acidified methanol solvent with different trifluoroacetic acid (TFA) contents of 0.5, 1.75 and 3% (v/v). The statistical evaluation was performed by running analysis of variance (ANOVA) and regression calculation to investigate the significance of the generated model. Results show that the generated regression models adequately explain the data variation and significantly represented the actual relationship between the independent variables and the responses. Analysis of variance (ANOVA) showed high coefficient determination values (R2) of 0.9687 for a*, 0.9621 for b* and 0.9758 for color saturation, thus ensuring a satisfactory fit of the developed models with the experimental data. Interaction between TFA content and extraction temperature exhibited to the highest significant influence on CIE color parameter.

In this work, we have investigated the influence of guanine as an organic dopant in dye-sensitized solar cell (DSSC) based on poly(vinylidinefluoride-co-hexafluoropropylene) (PVDF-HFP)/polyethylene oxide (PEO) polymer blend electrolyte along with binary iodide salts (potassium iodide (KI) and tetrabutylammonium iodide (TBAI)) and iodine (I2). The PVDF-HFP/KI + TBAI/I2, PVDF-HFP/PEO/KI + TBAI/I2 and guanine incorporated PVDF-HFP/PEO/KI + TBAI/I2 electrolytes were prepared by solution casting technique using DMF as solvent. The PVDF-HFP/KI + TBAI/I2 electrolyte showed an ionic conductivity value of 9.99 × 10−5 Scm−1, whereas, it was found to be increased to 4.53 × 10−5 Scm−1 when PEO was blended with PVDF-HFP/KI + TBAI/I2 electrolyte. However, a maximum ionic conductivity value of 3.67 × 10−4 Scm−1 was obtained for guanine incorporated PVDF-HFP/PEO/KI + TBAI/I2 blend electrolyte. The photovoltaic properties of all these polymer electrolytes in DSSCs were characterized. As a consequence, the power conversion efficiency of the guanine incorporated PVDF-HFP/PEO/KI + TBAI/I2 electrolyte based DSSC was significantly improved to 4.98% compared with PVDF-HFP/PEO/KI + TBAI/I2 electrolyte based DSSC (2.46%). These results revealed that the guanine can be an effective organic dopant to enhance the performance of DSSCs.

Chitosan and poly(ethylene oxide) powders have been mixed in different weight ratios. To each mixture, a fixed amount of ammonium iodide has been added. All mixtures have been dissolved in 1% acetic acid solution to form polymer blend electrolyte films by the solution cast technique. X-ray diffraction indicates that the polymer blend electrolytes are amorphous. Fourier transform infrared spectroscopy shows shifting of the amine, carboxamide and C O C bands to lower wavenumbers indicating the occurrence of complexation. Electrochemical impedance spectroscopy has been used to study the electrical properties of the samples. The ionic conductivity for 55 wt.% chitosan–45 wt.% NH 4 I electrolyte system is 3.73 × 10 −7 S cm −1 at room temperature and is increased to 3.66 × 10 −6 S cm −1 for the blended film (16.5 wt.% chitosan-38.5 wt.% PEO)–45 wt.% NH 4 I film. Dye-sensitized solar cells (DSSCs) have been fabricated by sandwiching the polymer electrolyte between the TiO 2 /dye photoelectrode and Pt counter electrode. DSSCs fabricated exhibits short-circuit current density ( J sc ) of 2.71 mA cm −2 , open circuit voltage ( V oc ) of 0.58 V and efficiency of 0.78% with configuration ITO/TiO 2 /N3 dye/(16.5 wt.% chitosan-38.5 wt.% PEO)–45 wt.% NH 4 I(+I 2 )/Pt/ITO and J sc of 2.84 mA cm −2 , V oc of 0.58 V and efficiency of 1.13% with configuration ITO/TiO 2 + Ag nanoparticles/N3 dye/(16.5 wt.% chitosan–38.5 wt.% PEO)–45 wt.% NH 4 I(+I 2 )/Pt/ITO.

In this work, urea is introduced into polyacrylonitrile (PAN)-based polymer electrolyte containing lithium bis(trifluoromethane)sulfonimide (LiTFSI) to form a deep eutectic solvent with urea and LiTFSI in the mole ratio of 1:3. The ambient ionic conductivity of the polymer electrolyte film is enhanced from 2.54 × 10−4 S cm−1 to 3.82 × 10−3 S cm−1 with the addition of urea. Infrared studies has revealed that urea interacts with the LiTFSI through coordination of Li+ ions onto the carbonyl (C O) group of urea, and hydrogen bonding possibly to the O atoms in the SO2 groups of TFSI− ions. Hydrogen bonding interactions of urea with DMF and PAN are also evident. The enhancement in conductivity is believed to be due to urea being involved in the dissociation of LiTFSI and its role as an additional ion conduction pathway through its carbonyl group.

The purpose of this paper is to evaluate the chromaticity and color saturation of anthocyanin extraction from fruit pericarps of Ixora siamensis in a poly(vinyl alcohol) (PVA) matrix. The colored PVA matrix was exposed to UV-B irradiation for 93 days at UV intensity of 17.55 lux. Anthocyanin colorant has been extracted using methanol acidified with 0.5% trifluoroacetic acid (TFA). Different concentrations of ferulic acid (FA) (0, 1, 2, 3, 4 and 5 wt.%) have been added to the anthocyanin extractions before mixing with PVA to form a coating system. The PVA-anthocyanin-FA mixtures have been coated on glass slides and kept overnight in the dark for curing before exposure to UV-B irradiation. The FA-free sample undergoes more color degradation compared to samples containing FA. The coating with 2% FA has the most stable color with chromaticity of 41% and color saturation of 0.88 compared to other FA containing coats. The FA-free coat exhibits 29% chromaticity and color saturation of 0.38 at the end of the experiment.

Solid electrolytes comprising 55 wt.%chitosan–45 wt.%NH 4 I, 33 wt.%chitosan–27 wt.%NH 4 I–40 wt.%EC (ethylene carbonate) and 11 wt.%chitosan–9 wt.%NH 4 I–80 wt.%BMII (1-butyl-3-methylimidazolium iodide) have been prepared by the solution cast technique. The conductivity for the 55 wt.%chitosan–45 wt.%NH 4 I electrolyte is 3.73 × 10 −7 S cm −1 at room temperature. Complexation between polymer and salt has been proven by Fourier transform infrared (FTIR) spectroscopy where the carbonyl and amine bands in the spectrum of chitosan acetate shifted from 1645 and 1557 cm −1 –1618 and 1508 cm −1 in the polymer–salt spectrum. The addition of 40 wt.%EC to the 55 wt.%chitosan–45 wt.%NH 4 I electrolyte increased its conductivity to 7.34 × 10 −6 S cm −1 . The conductivity of the chitosan–NH 4 I electrolyte increased to 8.47 × 10 −4 S cm −1 at room temperature on addition of 80 wt.%BMII. The plasticizer containing electrolyte is still a free standing film. The ionic liquid incorporated electrolyte is still solid, but with reduced mechanical stability due to the low polymer content. This shows that at such low content, chitosan is still able to host ionic conduction. A photovoltaic cell with configuration ITO/titanium dioxide (TiO 2 )–solid electrolyte with I - / I 3 - redox couple/ITO has been constructed using each electrolyte system. The short-circuit current density, J sc and open-circuit voltage, OCV obtained from the cell employing the polymer–salt electrolyte under white light illumination of intensity 56.4 mW cm −2 are 4.99 μA cm −2 and 0.15 V, respectively. The OCV for the cell with plasticizer containing electrolyte is 0.22 V and its J sc is 7.28 μA cm −2 . The solar cell with ionic liquid incorporated in the solid electrolyte exhibited an OCV of 0.26 V and J sc of 19.23 μA cm −2 , respectively.