| 1. |
- Bandara, T.M.W.J., 1968-, et al.
(författare)
-
A polymer electrolyte containing ionic liquid for possible applications in photoelectrochemical solar cells
- 2010
-
Ingår i: Journal of Solid State Electrochemistry. - 1432-8488. ; 14:7, s. 1221-1226
-
Tidskriftsartikel (refereegranskat)abstract
- Various iodide ion conducting polymer electrolytes have been studied as candidate materials for fabricating photoelectrochemical (PEC) solar cells and energy storage devices. In this study, enhanced ionic conductivity values were obtained for the ionic liquid tetrahexylammonium iodide containing polyethylene oxide (PEO)-based plasticized electrolytes. The analysis of thermal properties revealed the existence of two phases in the electrolyte, and the conductivity measurements showed a marked conductivity enhancement during the melting of the plasticizer-rich phase of the electrolyte. Annealed electrolyte samples showed better conductivity than nonannealed samples, revealing the existence of hysteresis. The optimum conductivity was shown for the electrolytes with PEO:salt= 100:15 mass ratio, and this sample exhibited the minimum glass transition temperature of 72.2 °C. For this optimum PEO to salt ratio, the conductivity of nonannealed electrolyte was 4.4×10−4 S cm−1 and that of the annealed sample was 4.6×10−4 S cm−1 at 30 °C. An all solid PEC solar cell was fabricated using this annealed electrolyte. The short circuit current density (ISC), the open circuit voltage (VOC), and the power conversion efficiency of the cell are 0.63 mA cm−2, 0.76 V, and 0.47% under the irradiation of 600 W m−2 light.
|
|
| 2. |
- Bandara, T.M.W.J., 1968-, et al.
(författare)
-
Dye-sensitized, nano-porous TiO2 solar cell with poly(acrylonitrile): MgI2 plasticized electrolyte
- 2010
-
Ingår i: Journal of Power Sources. - 0378-7753. ; 195:11, s. 3730-3734
-
Tidskriftsartikel (refereegranskat)abstract
- Dye-sensitized solar cells are promising candidates as supplementary power sources; the dominance in the photovoltaic field of inorganic solid-state junction devices is in fact now being challenged by the third generation of solar cells based on dye-sensitized, nano-porous photo-electrodes and polymer electrolytes. Polymer electrolytes are actually very favorable for photo-electrochemical solar cells and in this study poly(acrylonitrile)–MgI2 based complexes are used. As ambient temperature conductivity of poly(acrylonitrile)–salt complexes are in general low, a conductivity enhancement is attained by blending with the plasticizers ethylene carbonate and propylene carbonate. At 20 °C the optimum ionic conductivity of 1.9 × 10−3 S cm−1 is obtained for the (PAN)10(MgI2)n(I2)n/10(EC)20(PC)20 electrolyte where n = 1.5. The predominantly ionic nature of the electrolyte is seen from the DC polarization data. Differential scanning calorimetric thermograms of electrolyte samples with different MgI2 concentrations were studied and glass transition temperatures were determined. Further, in this study, a dye-sensitized solar cell structure was fabricated with the configuration Glass/FTO/TiO2/Dye/Electrolyte/Pt/FTO/Glass and an overall energy conversion efficiency of 2.5% was achieved under solar irradiation of 600 W m−2. The I–V characteristics curves revealed that the short-circuit current, open-circuit voltage and fill factor of the cell are 3.87 mA, 659 mV and 59.0%, respectively.
|
|
| 3. |
|
|
| 4. |
- Bandara, T.M.W.J., 1968-, et al.
(författare)
-
Efficiency enhancement in dye sensitized solar cells using gel polymer electrolytes based on a tetrahexylammonium iodide and MgI2 binary iodide system
- 2012
-
Ingår i: Physical Chemistry Chemical Physics. - 1463-9076. ; 14:24, s. 8620-8627
-
Tidskriftsartikel (refereegranskat)abstract
- Quasi-solid-state dye-sensitized solar cells have drawn the attention of scientists and technologists as a potential candidate to supplement future energy needs. The conduction of iodide ions in quasi-solid-state polymer electrolytes and the performance of dye sensitized solar cells containing such electrolytes can be enhanced by incorporating iodides having appropriate cations. Gel-type electrolytes, based on PAN host polymers and mixture of salts tetrahexylammonium iodide (Hex(4)N(+)I(-)) and MgI2, were prepared by incorporating ethylene carbonate and propylene carbonate as plasticizers. The salt composition in the binary mixture was varied in order to optimize the performance of solar cells. The electrolyte containing 120% Hex(4)N(+)I(-) with respect to weight of PAN and without MgI2 showed the highest conductivity out of the compositions studied, 2.5 x 10(-3) S cm(-1) at 25 degrees C, and a glass transition at -102.4 degrees C. However, the electrolyte containing 100% Hex(4)N(+)I(-) and 20% MgI2 showed the best solar cell performance highlighting the influence of the cation on the performance of the cell. The predominantly ionic behaviour of the electrolytes was established from the dc polarization data and all the electrolytes exhibit iodide ion transport. Seven different solar cells were fabricated employing different electrolyte compositions. The best cell using the electrolyte with 100% Hex(4)N(+)I(-) and 20% MgI2 with respect to PAN weight showed 3.5% energy conversion efficiency and 8.6 mA cm(-2) short circuit current density.
|
|
| 5. |
- Bandara, T.M.W.J., 1968-, et al.
(författare)
-
Mobile charge carrier concentration and mobility of a polymer electrolyte containing PEO and Pr4N+I- using electrical and dielectric measurements
- 2011
-
Ingår i: Solid State Ionics. - 0167-2738. ; 189:1, s. 63-68
-
Tidskriftsartikel (refereegranskat)abstract
- For the characterization and development of new electrolytes it is important to know the number of free charge carriers and their mobility. A new method has been developed to estimate the charge carrier density, n, and mobility, mu, for an electrolyte using dielectric measurements and a space charge relaxation model. In order to verify the applicability of this method, it has been tested with an aqueous KI solution electrolyte. The method was then applied to a polyethylene oxide (PEO) based polymer electrolyte. In the case of the polymer electrolyte, plasticized and non plasticized electrolytes intended for photo-electrochemical solar cells containing Pr4N+I- salt which is an iodide ion conductor at room temperature was used. The significant conductivity increase that occurs during the PEO crystallite melting is shown to be due to a large and abrupt increase of the concentration of mobile charge carriers. It is also shown that, for the PEO above the crystallite melting temperature, the introduction of the plasticizer results in an increased mobility. Results from the solution electrolyte show good agreement with known values.
|
|
| 6. |
|
|
| 7. |
- Bokalawela, R., 0, et al.
(författare)
-
H-2/Pt/Ce0.9Gd0.1O1.95/Pt/O-2 fuel cell operated in the intermediate temperature range 500-700 degrees C
- 2004
-
Ingår i: IONICS. - 0947-7047. ; 10:1-2, s. 84-87
-
Konferensbidrag (refereegranskat)abstract
- Ce0.9Gd0.1O1.95 (GCO), is one of the potential candidate electrolytes for intermediate temperature Solid Oxide Fuel Cells (ITSOFC). GCO has high oxide ion conductivity in the intermediate temperature range (500 - 700 degrees C) compared to other C1-yGdyO2-2/y compositions and the Gd3+ ion is the most appropriate dopant material compared to other rare earth materials such as Sm3+, Y3+, Zr3+, etc. Our results show that the fuel cell H-2/Pt/Ce0.9Gd0.1O1.95/O-2 operated in the temperature range 500 - 700 degrees C gives the maximum power densities 0.0049 W/cm(2) at 500 degrees C and 0.0126 W/cm(2) at 650 degrees C for cell voltages 0.6275 V and 0.6278 V, respectively, where the electrolyte was kept in 5% H-2(+ Argon) for 12 hours before use in the fuel cell. Maximum power densities are 0.0038 W/cm(2) at 500 degrees C and 0.0270 W/cm(2) at 650 degrees C for cell voltages 0.5986 and 0.5913 V, respectively, where the electrolyte was kept in 2 % O-2(+ Argon) for 12 hours before use in the fuel cell.
|
|
| 8. |
- Diosa, J.E., 0, et al.
(författare)
-
Dielectric relaxation in NH4HSO4 above room temperature
- 2006
-
Ingår i: SOLID STATE IONICS. - 0167-2738. ; 177:13-14, s. 1107-1110
-
Tidskriftsartikel (refereegranskat)abstract
- The dispersion curves of the dielectric response of NH4HSO4 show that the corrected imaginary part of permittivity, epsilon", and its real part epsilon' versus frequency reveal a dielectric relaxation around 9.1 x 10(5) Hz at 31 degrees C, which shifts to higher frequencies (similar to 10(6) Hz) as the temperatures increases. The relaxation frequency shows an activated relaxation process over the temperature range 31-83 degrees C with activation energy E-a = 0.14 eV, which is close to that derived from the dc conductivity. We suggest that the observed dielectric relaxation could be produced by the H+ jump and SO4- reorientation that cause distortion and change the local lattice polarizability inducing dipoles like HSO4-.
|
|
| 9. |
- Diosa, J.E., 0, et al.
(författare)
-
Dielectric relaxation studies in Cs2SO4
- 2006
-
Ingår i: FERROELECTRICS. - 0015-0193. ; 333, s. 253-258
-
Tidskriftsartikel (refereegranskat)abstract
- Dielectric measurements of Cs2SO4 show a distinct relaxation at low frequencies at several isotherms ( T < 651 degrees C). For example, the relaxation frequency is around 5.1 kHz at 376 degrees C and increases to approximately 1 MHz at 651 degrees C. The relaxation has an activation energy of 0.97 eV, which is in close agreement whit that of Cs+ transport. We suggest that the observed dielectric relaxation could be produced by the Cs+ jump and SO4- reorientation that cause distortion and change the local lattice polarizability inducing dipoles like CsSO4-.
|
|
| 10. |
- Diosa, J.E., 0, et al.
(författare)
-
Impedance spectroscopy studies of K2SO4 in the intermediate temperature regime
- 2005
-
Ingår i: Solid State Communications. - 0038-1098. ; 136:11-12, s. 601-604
-
Tidskriftsartikel (refereegranskat)abstract
- Impedance spectroscopy measurements of K2SO4 have been carried out from 5 Hz to 13 MHz over the temperature range 403-782 T. The plots of corrected imaginary part of permittivity, epsilon", and its real part epsilon' vs. frequency clearly show a new dielectric relaxation around epsilon") = 1.4 X 10(4) Hz at 403 degrees C, which shifts to higher frequencies (similar to 1 MHz) as the temperatures increases. The fma (calculated from the peak position of epsilon") vs. reciprocal T shows an activated relaxation process over the temperature range 403-600 T with activation energy E-a = 1.02 eV, which is close to that derived from the dc-conductivity, E-a = 1.15 eV. We suggest that the observed dielectric relaxation could be produced by the K+ jump and SO4- reorientation that cause distortion and change the local lattice polarizability inducing dipoles like KSO4-.
|
|
