L.P. Teo

TiO2/Chitosan-NH4I(+I2)-BMII-Based Dye-Sensitized Solar Cells with Anthocyanin Dyes Extracted from Black Rice and Red Cabbage

Dye sensitized solar cells (DSSCs) were fabricated using anthocyanin dye and polymer electrolyte with ammonium iodide (NH4I) salt. The study was designed to focus on increasing the efficiency of the DSSC. DSSC using 26.9 wt. % chitosan-22 wt. % NH4I(

Characterizations of Chitosan-Based Polymer Electrolyte Photovoltaic Cells

The membranes 55 wt.% chitosan-45 wt.% , 33 wt.% chitosan-27 wt.% -40 wt.% EC, and 27.5 wt.% chitosan-22.5 wt.% -50 wt.% buthyl-methyl-imidazolium-iodide (BMII) exhibit conductivity of , , and S , respectively, at room temperature. These membranes have been used in the fabrication of solid-state solar cells with configuration ITO//polymer electrolyte membrane/ITO. It is observed that the short-circuit current density increases with conductivity of the electrolyte. The use of anthocyanin pigment obtained by solvent extraction from black rice and betalain from the callus of Celosia plumosa also helps to increase the short-circuit current.

Conductivity studies on plasticised PEO/chitosan proton conducting polymer electrolyte

Abstract The effect of ethylene sulphite (ES) content on the conductivity, morphology and nature of polymer electrolytes based on polyethylene oxide (PEO) and chitosan blend doped with ammonium nitrate (NH4NO3) has been analysed in this study. The films produced by the solution cast technique were kept in a desiccator filled with silica gel before characterisation. The sample (23·8 wt-%PEO+35·7 wt-% chitosan)–39·7 wt-%NH4 NO3–0·8 wt-%ES exhibited the highest room temperature conductivity of the order 10–4 s cm–1. The conductivity–temperature relationship was found to obey Arrhenius rule. The activation energy for the highest conducting sample is 0·02 eV. From Jonschers universal power law, the trend of exponent s v. temperature showed that the conduction mechanism of the ions in the highest conducting sample can be explained by the quantum mechanical tunnelling (QMT) model. Scanning electron microscopy (SEM) revealed that surfaces of samples containing ES are porous.

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

Abstract 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°C. The Li2SnO3 precursor was then sintered at 800°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°C for 9 h produced Li2SnO3 with lattice parameters a = 5·302 Å, b = 9·167 Å and c = 10·032 Å, volume of 479·922 Å3 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.

Plasticised polymer electrolytes based on PMMA grafted natural rubber–LiCF3SO3–PEG200

Abstract Polymer electrolyte membranes that consist of 70 wt-% natural rubber grafted with 30 wt-% poly(methyl methacrylate) (MG30) and 30 wt-% lithium trifluoromethane sulphonate (LiTf) salt have been investigated with various concentrations of poly(ethylene glycol) 200 (PEG200). The formation of polymer–salt complexes has been confirmed by Fourier transform infrared spectral studies. X-ray diffraction studies further confirmed that all the samples prepared are amorphous. The highest conducting sample has the composition of 63 wt-%MG30–27 wt-%LiTf–10 wt-%PEG with conductivity of 3·65×10−4 S cm−1 at 298 K. From differential scanning calorimetry studies, the glass transition temperature Tg is found to increase from −63 to −54°C with the increase in PEG concentration at 30 wt-%PEG200. The ionic transference number of mobile ions has been estimated using Wagner’s polarisation method, and the results reveal that the conducting species are mainly ions.