| 1. |
- Bandara, T M W J, 1968, et al.
(author)
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Conductivity behaviour in novel quasi-solid-state electrolyte based on polyacrylonitrile and tetrahexylammonium iodide intended for dye sensitized solar cells
- 2013
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In: Journal of the National Science Foundation of Sri Lanka. - : Sri Lanka Journals Online (JOL). - 1391-4588 .- 2362-0161. ; 41:3, s. 175-184
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Journal article (peer-reviewed)abstract
- The conduction of iodide ions in gel polymer electrolytes and the performance of dye sensitized solar cells containing such an electrolyte can be enhanced by incorporating a salt having a bulky cation. In this work, polyacrylonitrile (PAN) and Hex(4)N(+)I(-) based gel electrolytes with ethylene carbonate and propylene carbonate as plasticizers have been studied. The variation of conductivity and molar conductivity with salt concentration has been discussed in order to understand the mechanism of iodide ion conductivity in this system. Out of the various compositions studied, the electrolyte containing 120 % salt with respect to weight of PAN showed the highest conductivity, 2.0 X 10(-3) Scm(-1) at 25 degrees C and a glass transition at - 102.3 degrees C. The electrolytes exhibit predominantly ionic behaviour and because of the bulky cation a negligible cationic transport is shown. A quasi-solid-state dye sensitized solar cell was fabricated employing the optimized gel electrolyte. This cell showed an energy conversion efficiency of 3.1 % and a short circuit current density of 8.1 mAcm(-2) under irradiation of 1000 Wm(-2).
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| 2. |
- Bandara, T M W J, 1968, et al.
(author)
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Effect of cation size on the performance of dye sensitized nanocrystalline TiO2 solar cells based on quasi-solid state PAN electrolytes containing quaternary ammonium iodides
- 2013
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In: Electrochimica Acta. - : Elsevier BV. - 0013-4686. ; 109, s. 609-616
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Journal article (peer-reviewed)abstract
- The performance of dye sensitized nanocrystalline TiO2 solar cells based on quasi-solid state PAN electrolytes containing a series of six quaternary ammonium iodide salts NH4I, Eth(4)NI, Prop(4)NI, But(4)NI, Pent(4)NI, Hex(4)NI with different cation sizes has been evaluated. Even though the total ionic conductivity decreases with increasing cation size from NH4I to Hex(4)NI, the iodide ion conductivity in the electrolytes increases with cation size. The open circuit photovoltage (V-oc) of the dye sensitized solar cells also increases with cation radius. The efficiency of the DSSCs varies with cation size and exhibits a maximum for Prop(4)NI salt. The short circuit photo current density (J(sc)) follows a similar variation with cation size, suggesting a strong correlation between the cation size dependence of efficiency and J(sc). The DSSC fabricated with tetrapropylammonium iodide exhibited the maximum efficiency of 4.30% with maximum J(sc) of 10.78 mA cm(-2) and a V-oc of 0.746 V. The results have been interpreted on the basis of "the electrolyte effects" where J(sc) is determined essentially by the iodide ion conductivity and "the electrode effects" where the J(sc) and V-oc are determined by the cation adsorption in the dyed TiO2 electrode and resulting electron dynamics at the semiconductor/electrolyte interface. For DSSCs with small cations, electrolyte effects appear to be dominating and rate determining while for DSSCs with larger cations, electrode effects appear to be dominating and rate determining. (C) 2013 Elsevier Ltd. All rights reserved.
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| 3. |
- Bandara, T M W J, 1968, et al.
(author)
-
Efficiency enhancement in dye sensitized solar cells using gel polymer electrolytes based on a tetrahexylammonium iodide and MgI2 binary iodide system
- 2012
-
In: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 14:24, s. 8620-8627
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Journal article (peer-reviewed)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.
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| 4. |
- Bandara, T M W J, 1968, et al.
(author)
-
Efficiency enhancement of dye-sensitized solar cells with PAN:CsI:LiI quasi-solid state (gel) electrolytes
- 2014
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In: Journal of Applied Electrochemistry. - : Springer Science and Business Media LLC. - 1572-8838 .- 0021-891X. ; 44:8, s. 917-926
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Journal article (peer-reviewed)abstract
- While many attempts have been made in the recent past to improve the power conversion efficiencies of dye-sensitized solar cells (DSSCs), only a few reports can be found on the study of these cells using binary iodides in the gel polymer electrolyte. This paper reports the effect of using a binary mixture of (large and small cation) alkaline salts, in particular CsI and LiI, on the efficiency enhancement in DSSCs with gel polymer electrolytes. The electrolyte with the binary mixture of CsI:LiI = 1:1 (by weight) shows the highest ionic conductivity 2.9 x 10(-3) S cm(-1) at 25 A degrees C. DC polarization measurements showed predominantly ionic behavior of the electrolyte. The density of charge carriers and mobility of mobile ions were calculated using a newly developed method. The temperature dependent behavior of the conductivity can be understood as due to an increase of both the density and mobility of charge carriers. The solar cell with only CsI as the iodide salt gave an energy conversion efficiency of similar to 3.9 % while it was similar to 3.6 % for the cell with only LiI. However, the electrolyte containing LiI:CsI with mass ratio 1:1 showed the highest solar cell performance with an energy conversion efficiency of similar to 4.8 % under the irradiation of one Sun highlighting the influence of the mixed cation on the performance of the cell. This is an efficiency enhancement of 23 %.
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| 5. |
- Bandara, T M W J, 1968, et al.
(author)
-
Tetrahexylammonium iodide containing solid and gel polymer electrolytes for dye sensitized solar cells
- 2012
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In: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 14, s. 1607-1612
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Conference paper (peer-reviewed)abstract
- The performance evaluation plays a more and more important role in the modern enterprise management, and the method of evaluation system on enterprise performance is always an important question in the theory and practice. So this paper set up a scientific, reasonable performance evaluation index system which was especially suitable for the small and medium third party logistics enterprise from the four levels of financial, customers, business and innovation. Meanwhile, according to the index system, it gave a performance evaluation with the Chinese access logistics corporation. The results showed that the construction of the index system was reasonable, and the evaluation results also were reliable.
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| 6. |
- Dintcheva, N. T., et al.
(author)
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Rheological behavior of PAN-based electrolytic gel containing tetrahexylammonium and magnesium iodide for photoelectrochemical applications
- 2013
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In: Rheologica Acta. - : Springer Science and Business Media LLC. - 1435-1528 .- 0035-4511. ; 52:10-12, s. 881-889
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Journal article (peer-reviewed)abstract
- Polymeric gel electrolyte systems have gained great interest in the last few years due to their suitability for the manufacturing of ionic devices, for example, for dye-sensitized solar cells (DSSCs). In this work, the rheological behavior at fixed temperatures and at fixed frequency of complex systems based on polyacrylonitrile (PAN) and plasticizers such as ethylene carbonate (EC) and propylene carbonate (PC) containing tetrahexylammonium (Hex(4)NI) and magnesium iodide (MgI2) was studied. These results for these PAN-EC-PC gels suggest a structural change of the "strong-to-weak" type at about 60 A degrees C and the beginning of the gel-sol transition at about 75 A degrees C. These transitions occur at higher temperatures for polymer electrolyte gels containing Hex(4)NI and even higher with MgI2, suggesting the possibility of post-factum treatments of the gels and of the DSSCs to improve their performance. The rheological results suggest that the progressive substitution of Hex(4)NI with MgI(2)leads to a significant improvement in the rheological behavior of the PAN-based electrolytic gel due to the decrease of the mobility of the macromolecules and probably to an increase of the interaction between the inorganic ions and the macromolecules. Moreover, when these gels were used in DSSCs, the sample containing 80(Hex(4)NI)/40(MgI2) showed the best performance considering its rheological and calorimetric behavior as well as energy conversation efficiency and short-circuit current density.
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| 7. |
- Dissanayake, MAKL, et al.
(author)
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Efficiency enhancement in dye sensitized solar cells based on PAN gel electrolyte with Pr4NI + MgI2 binary iodide salt mixture
- 2013
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In: Journal of Applied Electrochemistry. - : Springer Science and Business Media LLC. - 1572-8838 .- 0021-891X. ; 43:9, s. 891-901
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Journal article (peer-reviewed)abstract
- The effect of using a binary iodide salt mixture in N719 dye-sensitized TiO2 solar cells (DSSCs) is investigated. The cells use tetrapropylammonium iodide (Pr4NI) and magnesium iodide (MgI2) in a plasticized polyacrylonitrile gel in glass/FTO/nano-porous TiO2/gel, I-2/Pt/FTO/glass solar cell structure. The salt composition in the gel electrolyte is varied to optimize the efficiency of DSSCs. The DSSCs with MgI2 or Pr4NI as the only iodide salt showed the efficiencies 2.56 and 4.16 %, respectively, under AM 1.5 (100 mW cm(-2)) illumination while the DSSC with mixed cations with 18.4:81.6 MgI2:Pr4NI molar ratio shows the highest efficiency of 5.18 %. Thus the efficiency enhancement, relative to the high efficiency end member is about 25 %. DC polarization measurements establish the predominantly ionic behavior of the electrolytes, and show that the variation of efficiency with salt composition correlates with the change in short circuit photocurrent density (J (sc)), which appears to be governed by the iodide ion conductivity. It is also found that J (sc) correlates with the iodide ion transference number estimated from DC polarization data taken with non-blocking iodine electrodes. This study suggests that binary iodide mixtures may be used to obtain efficiency enhancement in different types of DSSCs based on polymeric, gel, or solvent electrolytes.
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| 8. |
- Arof, A. K., et al.
(author)
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Quasi solid state dye-sensitized solar cells based on polyvinyl alcohol (PVA) electrolytes containing redox couple
- 2014
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In: Optical and Quantum Electronics. - : Springer Science and Business Media LLC. - 0306-8919 .- 1572-817X. ; 46:1, s. 143-154
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Journal article (peer-reviewed)abstract
- Quasi solid state dye-sensitized solar cells (DSSCs) have been fabricated with electrolytes containing I-/I-3(-) redox couple using 80% hydrolyzed polyvinyl alcohol (PVA) doped with potassium iodide (KI) and a mixture of potassium iodide and tetrapropyl ammonium iodide (Pr4NI) salts. The quasi solid state gel polymer electrolytes were prepared using 1: 1 ethylene carbonate (EC): propylene carbonate (PC) mixture. The solar cells have the structure of ITO/TiO2/N-3-Dye/electrolyte/Pt/ITO. The conductivity of the electrolytes has been calculated from the bulk resistance value determined using the electrochemical impedance spectroscopy. The performance of the DSSCs has been studied by varying the concentration of the doping salts in the electrolyte and incident light intensity. The DSSC fabricated with the KI salt electrolyte containing 9.9 wt% PVA, 39.6 wt% EC, 39.6 wt% PC, 10.9 wt% KI(+I-2) exhibited the best power conversion efficiency of 1.97 %. However, the DSSC with a double-salt electrolyte containing 9.9 wt% PVA: 39.6 wt% EC: 39.6 wt% PC: (6.5 wt% KI: 4.4 wt% Pr4NI) (+I-2) exhibited a higher efficiency of 3.27% under 100 mW/cm(2) light intensity. The efficiency of this cell increased to 4.59 % under dimmer light of intensity of 54 mW/cm(2).
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| 9. |
- Bandara, T M W J, 1968, et al.
(author)
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Efficiency of 10 % for quasi-solid state dye-sensitized solar cells under low light irradiance
- 2015
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In: Journal of Applied Electrochemistry. - : Springer Science and Business Media LLC. - 0021-891X .- 1572-8838. ; 45:4, s. 289-298
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Journal article (peer-reviewed)abstract
- Polyacrylonitrile-based gel electrolytes were prepared using tetrapropylammonium iodide salt for dye-sensitized solar cells (DSSCs). The optimized gel electrolyte exhibited an ionic conductivity of 2.6 mS cm(-1) at 25 A degrees C and the DSSC fabricated with this gel electrolyte showed open-circuit voltage, short-circuit current density, fill factor, and efficiency of 0.71 V, 11.8 mA, 51, and 4.2 %, respectively, under one sun irradiation. The efficiency of the cell increases increased with decreasing solar irradiance achieving 10 % efficiency and 80 % fill factor at 3 mW cm(-2) a low irradiance value of 3 mW cm(-2). Lower efficiencies at higher intensities were attributed to transport limitation of the redox mediators at high irradiation intensities. This work suggests that quasi-solid state DSSCs can reach efficiencies close to that of liquid electrolyte-based cells at low irradiance levels. The results open up new vistas on efficiency improvement in DSSCs by optical manipulation and control of DSSCs.
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| 10. |
- Bandara, T M W J, 1968, et al.
(author)
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Quasi solid state polymer electrolyte with binary iodide salts for photo-electrochemical solar cells
- 2014
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In: International Journal of Hydrogen Energy. - : Elsevier BV. - 0360-3199. ; 39:6, s. 2997-3004
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Journal article (peer-reviewed)abstract
- Quasi-solid-state polymer electrolytes can be used in dye sensitized solar cells (DSSCs) in order to overcome various problems associated with liquid electrolytes. Prior to fabricating commercially viable solar cells, the efficiency of quasi solid state DSSCs needs to be improved. Using electrolytes with a binary iodide mixture is a novel technique used to obtain such efficiency enhancement. In this work we report both conductivity and solar cell performance enhancements due to incorporation of a mixture containing LiI and tetrahexylammonium iodide in a quasi-solid-state electrolyte. The conductivity of the electrolyte increases with added amounts of Lit and thus the highest conductivity, 3.15 x 10(-3) S cm(-2) at 25 degrees C, is obtained for the electrolyte 100 wt% LiI. The predominantly ionic behavior of the electrolytes was established from dc polarization measurements. The iodide ion conductivity, measured using iodine pellet electrodes decreased somewhat with increasing amount of LiI even though the overall conductivity increased. However, the highest efficiency was obtained for the DSSC containing a polymer electrolyte with Hex(4)N(+)I:LiI = 1:2 mass ratio. This cell had the largest short circuit current density of about 13 mA cm(-2) and more than 4% overall energy conversion efficiency. The results thus show that electrolytes with Hex(4)N(+)I/LiI mixed iodide system show better DSSC performance than single iodide systems. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
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