Application of LiBOB-based liquid electrolyte in co-sensitized solar cell

Co-sensitized solar cells have been fabricated using metal complex N3 dye and Ag2S/CdS quantum dots coupled with LiBOB-based liquid electrolyte. Quantum dots (QDs) were synthesized via the successive ionic layer adsorption and reaction (SILAR) route. The absorbance and band gap energy of Ag2S and CdS QDs were determined. Their refractive indices were observed to be in the range of 1.5175-1.5200. It has been shown that LiBOB-based liquid electrolyte is able to function in the QD/N3 dye co-sensitized solar:cells but some stability issues of the QD were observed in the electrolyte system containing iodide whereby the QD-sensitized TiO2 was easily etched. Overall efficiencies and fill factors of the co-sensitized solar cells varied from 0.98% to 1.66% and 40% to 46% respectively. CdS QD was shown to be effective when coupled with polysulfide electrolyte while Ag2S QD was favorable towards the LiBOB-based liquid electrolyte

A novel LiSnVO4 anode material for lithium-ion batteries

In this work, a new material LiSnVO4 has been prepared via sol-gel method utilizing ammonium metavanadate, acetates of tin and lithium as starting materials, and nitric acid and oxalic acid as complexing agents. The amount of starting materials used has been chosen so that the mole ratio of Li/Sn/V is 1:1:1. The sol-gel precursor has been sintered at 700 °C for 6 h. Based on thermogravimetry analysis (TGA) analysis, the formation mechanism suggested the product to be LiSnVO4. Energy-dispersive X-ray analysis (EDX) reveals the ~1:1 ratio of Sn:V. EDX results agree reasonably with the formation mechanism from TGA analysis that the Sn:V ratio is 1:1. Results from X-ray photoelectron spectroscopy (XPS) indicate that the oxidation states of Li, Sn, and V are +1, +2, and +5, respectively. Since there is no ICDD data available to match the XRD diffractogram of the material obtained, CMPR and powder diffraction data interpretation and indexing program (POWD) softwares have been used to predict the crystal structure system to be tetragonal (similar to that of SnO2). A fabricated LiSnVO4//Li cell can deliver a large initial irreversible discharge capacity of 1270 mAh g−1 and reversible capacity of 305.4 mAh g−1 at the end of second cycle, which drops to 211 mAh g−1 at the end of 53rd cycle. The capacity retention is 69 % with respect to the second discharge capacity

Conductivity studies of poly(ethylene oxide)(PEO)/poly(vinyl alcohol) (PVA) blend gel polymer electrolytes for dye-sensitized solar cells

Poly(ethylene oxide)(PEO)–poly(vinyl alcohol) (PVA) blend-based gel polymer electrolytes (GPEs) have been prepared by blending equal weights of PEO and PVA in ethylene carbonate (EC), dimethyl sulfoxide (DMSO), tetrabutylammonium iodide (TBAI), and iodine crystals (I2). The conductivity, diffusion coefficient, number density, and ion mobility of the electrolytes have been calculated from the impedance data obtained from electrochemical impedance spectroscopy (EIS) measurements. The GPE with the composition of 7.02 wt%, PVA, 7.02 wt% PEO, 30.11 wt% ethylene carbonate (EC), 30.11 wt% DMSO, 24.08 wt% TBAI and 1.66 wt% I2 exhibits the highest conductivity of 5.5 mS cm−1 at room temperature. Dye-sensitized solar cells (DSSCs) with configuration fluorine tin oxide (FTO)/titanium dioxide/N3-dye/GPE/platinum/FTO have been fabricated and tested under the white light of intensity 100 mW cm−2. The DSSC containing the highest conducting GPE exhibits the highest power conversion efficiency, η of 5.36 %

Conductivity and dielectric studies of Li2SnO3

Lithium stannate (Li2SnO3) has been prepared by solution evaporation method. The precursor obtained is sintered at 800A degrees C for 5, 6, and 7 h, respectively. X-ray diffractogram confirmed that the sample obtained after sintering is Li2SnO3. The pelletized Li2SnO3 after heating at 500 A degrees C for 3 h is used for electrochemical impedance spectroscopy characterization. Impedance measurements have been carried out over frequency range from 50 Hz to 1 MHz and temperature range from 563 to 633 K. The conductivity-temperature relationship is Arrhenian. Several important parameters such as activation energy, ionic hopping frequency and its rate, carrier concentration term, mobile ion number density, ionic mobility, and diffusion coefficient have been determined. The characteristics of log conductivity and log ionic hopping rate against temperature for the system suggest that the conduction and ionic hopping processes are thermally activated. The values of activation energy for conduction and relaxation processes as well as activation enthalpy for ionic hopping are about the same

Characteristics of TiO2/Solid electrolyte junction solar cells with I-/I-3(-) redox couple

Solid electrolytes comprising 55 wt.%chitosan-45 wt.%NH4I, 33 wt.%chitosan-27 wt.%NH4I-40 wt.%EC (ethylene carbonate) and 11 wt.%chitosan-9 wt.%NH4I-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.%NH4I electrolyte is 3.73 x 10(-7) S cm(-1) at room temperature. Complexation between polymer and salt has been proven by Fourier transform infrared (FUR) 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.%NH4I electrolyte increased its conductivity to 7.34 x 10(-6)S cm(-1). The conductivity of the chitosan-NH4I electrolyte increased to 8.47 x 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 (TiO2)-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 mu A 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 mu A 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 mu A cm(-2), respectively. (C) 2009 Elsevier B.V. All rights reserved

Synthesis of α-Mo2C by Carburization of α-MoO3 Nanowires and Its Electrocatalytic Activity towards Tri-iodide Reduction for Dye-Sensitized Solar Cells

Nanowire-shaped α-MoO3 was synthesized on a large scale by hydrothermal route. Nanocrystalline α-Mo2C phase was obtained by the carburization of α-MoO3 nanowires with urea as a carbon source precursor. The phase purity and crystalline size of the synthesized materials were ascertained by using powder X-ray diffraction. The shape and morphology of synthesized materials were characterized by field-emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM). The electrocatalytic activity of α-Mo2C for I−/I3− redox couple was investigated by the cyclic voltammetry. The synthesized α-Mo2C was subsequently applied as counter electrode in dye-sensitized solar cells to replace the expensive platinum

An optimized poly(vinylidene fluoride-hexafluoropropylene)–NaI gel polymer electrolyte and its application in natural dye sensitized solar cells

Gel type polymer electrolytes with PVDF-HFP as polymer host, NaI salt and EC/PC as plasticizers have been prepared and optimized for use in a dye sensitized solar cell (DSSC). The polymer electrolyte containing 48 wt. % (PVDF-HFP)–32 wt. % NaI–20 wt. % (EC/PC) exhibits the highest room temperature conductivity of 1.53 × 10−4 S cm−1. This electrolyte has been used in the fabrication of a DSSC with the configuration FTO/TiO2/natural dye/electrolyte/Pt/FTO. The natural dyes used anthocyanin and chlorophyll were solvent extracted from black-rice and pandanus amaryllifolius leaves respectively. UV-vis absorption spectra of anthocyanin, chlorophyll and the mixture of anthocyanin and chlorophyll in the volume ratio 1:1 were recorded. The anthocyanin shows an absorption peak at 532 nm. In the same region chlorophyll absorption shows a peak at 536 nm and also has a prominant peak at 665 nm. On mixing anthocyanin and chlorophyll two prominant peaks are observed at 536 and 665 nm. The DSSC containing the dye mixture exhibits the best performance with a short-circuit current density of 2.63 mA cm−2, open-circuit voltage of 0.47 V, fill factor of 0.58 and the highest photo-conversion efficiency of 0.72% under the illumination of 100 mW cm−2 white light. Under illumination of lower light intensity of 60 mW cm−2 and 30 mW cm−2, the fill factor enhanced from 0.58 to 0.59 and 0.60 and the photo-conversion efficiency increased from 0.72% to 1.11% and 1.85% respectively

Effect of tetrabutylammonium iodide content on PVDF-PMMA polymer blend electrolytes for dye-sensitized solar cells

The influence of tetrabutylammonium iodide on the polyvinylidene fluoride-poly(methyl methacrylate)-ethylene carbonate (PVDF-PMMA-EC)-I2 polymer blend electrolytes was investigated and optimized for use in a dye-sensitized solar cell. The different weight ratios (50, 60, 70, and 80 %) of tetrabutylammonium iodide (TBAI)-added PVDF-PMMA-EC-I2 polymer electrolytes were prepared. The prepared solid polymer blend electrolytes were characterized by using various techniques such as Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and electrochemical impedance spectroscopy (EIS). The FT-IR spectra revealed the interaction among all composition of polymer electrolytes. The influence of TBAI salt on the ionic conductivity of polymer electrolytes was studied using electrochemical impedance spectroscopy. The polymer electrolyte containing 60 % of TBAI in PVDF-PMMA-EC-I2 showed the highest room temperature conductivity of 5.10 × 10−3 S cm−1. The fabricated DSSC using PVDF-PMMA-EC-I2 polymer electrolytes with 60 % of TBAI showed the best performance with a short-circuit current density of 8.0 mA cm−2, open-circuit voltage of 0.66 V, fill factor of 0.65, and the overall power conversion efficiency of 3.45 % under an illumination of 100 mW cm−2. Hence, the weight content of organic iodide salt in polymer electrolytes influences the overall performance of dye-sensitized solar cells

Effect of the potassium iodide in tetrapropyl ammonium iodide-polyvinyl alcohol based gel polymer electrolyte for dye-sensitized solar cells

Low ionic conductivity in gel polymer electrolytes with large cations is undoubtedly a critical issue. This research’s main objective was to explore potassium iodide influences on the conductivity in gel polymer electrolytes. PVA-based gel polymer electrolytes (GPEs), including tetrapropyl ammonium iodide and potassium iodide have been prepared. The GPEs have been characterized by X-ray diffraction (XRD) and electrical impedance spectroscopy (EIS). The GPEs prepared haves been recognized as an amorphous region through the X-ray diffraction analysis. The GPE sample’s conductivity (100 wt% of tetrapropyl ammonium iodide) of 6.24 × 10− 3 S cm− 1 was the lowest. The existence of potassium iodide in the GPE system improves the conductivity. The conductivity of 9.72 × 10− 3 S cm− 1 of GPE containing 30 wt% of tetrapropyl ammonium iodide and 70 wt% of potassium iodide was the highest derived from the EIS analysis. All prepared GPEs have the potential to be used for dye-sensitized solar cell applications. The dye sensitized solar cell efficiency has been improved by ~30% if potassium iodide exists in the GPE system

Characterisation of Li2SnO3 by solution evaporation method using nitric acid as chelating agent

Lithium stannate (Li2SnO3) was prepared by solution evaporation method utilising acetates of tin and lithium as starting materials. From thermogravimetric analysis, no weight loss was observed at temperatures above 800 degrees C. The Li2SnO3 precursor was then sintered at 800 degrees C for 5, 6, 7, 8 and 9 h, respectively. X-ray diffraction confirmed the sample to be Li2SnO3 with a monoclinic cell structure. The lattice parameters, volume and density of Li2SnO3 at different sintering hours were calculated. Sintering the precursor at 800 degrees C for 9 h produced Li2SnO3 with lattice parameters a=5.302 angstrom, b=9.167 angstrom and c=10.032 angstrom, volume of 479.922 angstrom(3) and density of 4.999 g cm(-3). The product was used as anode active material in the fabrication of a lithium half cell. The Li2SnO3//1M LiPF6/ethylene carbonate/diethyl carbonate (v/v=1 : 2)//Li cell exhibited an initial discharge capacity of 363.1 mA h g(-1)