| 1. |
- Bandara, Tmwj, et al.
(författare)
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Efficiency enhancement and chrono-photoelectron generation in dye-sensitized solar cells based on spin-coated TiO2 nanoparticle multilayer photoanodes and a ternary iodide gel polymer electrolyte
- 2023
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Ingår i: Journal of Materials Science-Materials in Electronics. - 0957-4522. ; 34:28
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Tidskriftsartikel (refereegranskat)abstract
- The effect of the thickness of a multilayer TiO2 photoanode on the performance of a dye-sensitized solar cell (DSC) made with a polyethylene oxide-based gel polymer electrolyte containing ternary iodides and performance enhancer 4-tert-butylpyridine is studied. Multilayer photoanodes consisting of up to seven layers of TiO2 nano-particles (13 nm and 21 nm) are prepared by spin coating of successive layers. XRD results confirm the predominant presence of the anatase phase of TiO2 in the multilayer structure after sintering. The SEM images reveal the formation of a single TiO2 film upon sintering due to merging of individually deposited layers. The photocurrent density (J(SC)) and the efficiency increase with the number of TiO2 layers exhibiting the maximum efficiency and J(SC) of 5.5% and 12.5 mA cm(-2), respectively, for the 5-layered electrode of total thickness 4.0 mu m with a 9.66 x 10(-8) mol cm(-2) surface dye concentration. The present study introduces a method of determining the rate of effective photoelectron generation and the average time gap between two successive photon absorptions where the respective results are 1.34 molecule(-1) s(-1) and 0.74 s for the most efficient cell studied in this work.
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| 2. |
- Bandara, T M W J, 1968, et al.
(författare)
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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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Ingår i: 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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Tidskriftsartikel (refereegranskat)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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| 3. |
- Bandara, T M W J, 1968, et al.
(författare)
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Efficiency enhancement of dye-sensitized solar cells with PAN:CsI:LiI quasi-solid state (gel) electrolytes
- 2014
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Ingår i: Journal of Applied Electrochemistry. - : Springer Science and Business Media LLC. - 1572-8838 .- 0021-891X. ; 44:8, s. 917-926
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Bandara, T M W J, 1968, et al.
(författare)
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Transport parameters of charge carriers in PEO-LiTf-based, plasticized, composite, and plasticized-composite electrolytes intended for Li-ion batteries
- 2022
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Ingår i: Ionics. - : Springer Science and Business Media LLC. - 0947-7047 .- 1862-0760. ; 28:6, s. 2701-2714
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Tidskriftsartikel (refereegranskat)abstract
- Solid polymer electrolytes are a key component in many electrochemical devices such as dye-sensitized solar cells, batteries, and supercapacitors. In this study, three electrolytes based on polyethylene oxide (PEO) host polymer, ethylene carbonate (EC) plasticizer, and Al2O3 filler were investigated. The polymer electrolytes (PEO)9(EC)9(LiCF3SO3)2, (PEO)9(LiCF3SO3)2(Al2O3)0.75, and (PEO)9(EC)9(LiCF3SO3)2(Al2O3)0.75 were characterized by analyzing DC conductivity, the frequency dependence of AC conductivity, and complex dielectric function. The conductivities of the plasticized, composite, and plasticized-composite electrolytes at 26 °C increase from 6.25, 0.009, and 2.96 mS cm-1 to 21.5, 0.12, and 11.4 mS cm-1, respectively, when the temperature increased to 70 °C. For the in-depth analysis of electrolytes, dielectric analysis was used to determine the charge carrier density (n), mobility (μ), and diffusion coefficient (D) using a newly developed method. Further, the investigation extended to study the temperature dependence of n, D, and μ. The study reveals that EC can increase the ionic conductivity by increasing n, and conversely, filler contributes by increasing μ, respectively. At 26 °C, (PEO)9(EC)9(LiCF3SO3)2(Al2O3)0.75 shows D, μ, and n of 3.8×10-11 m2 s-1, 1.5×10-9 m2 V-1 s-1, and 1.3×1027 m-3, respectively. The values obtained for D, μ, and n parameters of the plasticized electrolytes agree with those available for similar electrolytes, while the composite electrolyte showed considerably lower values for n. The complex impedance analysis can be used to determine transport parameters of all the types (plasticized, composite, and plasticized composite) of polymer electrolytes.
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| 5. |
- Bandara, Tmwj, et al.
(författare)
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Nano structured diatom frustules incorporated into TiO2 photoelectrodes to enhance performance of quasi-solid-state dye-sensitized solar cells
- 2023
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Ingår i: Optical Materials. - 0925-3467. ; 146
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Tidskriftsartikel (refereegranskat)abstract
- Diatom frustules are incorporated into multilayer photoelectrodes intending to enhance efficiency in dyesensitized solar cells utilizing their light interaction properties. A specific, but ubiquitous in all oceans, pennate-type diatom frustules were used to form the composite layers. Single, double, and triple-layer photoelectrodes were constructed with pure TiO2 (control measurements) as well as with a TiO2/diatom frustule composite. The electrodes were prepared using TiO2 nanoparticles of two sizes (13 and 21 nm) and were analyzed using UV visible absorption and XRD spectra. The morphology of frustules and electrodes were analyzed using scanning electron microscopy. The performance for each photoanode configuration was measured by assembling photoelectrochemical solar cells fabricated with a Pt counter electrode and a gel polymer electrolyte that excludes volatile solvents. The efficiency of the control cell is 3.37%. After replacing the topmost TiO2 layer with a TiO2/diatom frustule composite layer, efficiency increases to 6.78%. This is an impressive efficiency enhancement of 101%. The short circuit current density of frustule-incorporated threelayer cells is 18.1 mA cm-1 while for the control cell it is 8.98 mA cm-1. The enhanced efficiency of cells made with TiO2/diatom frustule composite electrodes and a polyethylene oxide-based gel polymer electrolyte can be attributed to the improved light absorption by the photoanode due to optical scattering and light-trapping effects caused by the presence of diatom frustules. Frustules also can assist in enhancing dye adsorption by increasing the effective specific surface area of the composite photoelectrode due to their nanoporous structure.
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| 6. |
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| 7. |
- Kreuger, A., et al.
(författare)
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[Acute lymphatic leukemia in Swedish children 1968-2001. The marked improvement of the survival can be ascribed to successful treatment]
- 2004
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Ingår i: Lakartidningen. - 0023-7205. ; 101:48
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Tidskriftsartikel (refereegranskat)abstract
- This is a survey of acute lymphoblastic leukemia (ALL) in Swedish children from 1968 to 2001. The survival has increased from a few per cent to more than 80 per cent of children with ALL in these national complete patient materials. Changes in diagnosis and treatment are discussed as well as the importance of supportive care. The favorable results can almost certainly be ascribed to continuous cooperation between the Swedish pediatric departments, the Swedish Child Leukemia Group and international working groups.
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| 8. |
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| 9. |
- Salomonsson, S., et al.
(författare)
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A Population-based Investigation of the Autoantibody Profile in Mothers of Children with Atrioventricular Block
- 2011
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Ingår i: Scandinavian Journal of Immunology. - Oxford : Blackwell Publishing. - 0300-9475 .- 1365-3083. ; 74:5, s. 511-517
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Tidskriftsartikel (refereegranskat)abstract
- The objective of the study was to investigate the antigen specificity and occurrence of individual autoantibodies in mothers of children diagnosed with atrioventricular (AV) block in a nation-wide setting. Patients with AV block detected before 15 years of age were identified using national quality registries as well as a network of pediatric and adult cardiologists and rheumatologists at the six university hospitals in Sweden. Patients with gross heart malformations, surgically or infectiously induced blocks were excluded. Blood samples were obtained from the mothers and maternal autoantibody profile, including the occurrence of antibodies against Ro52, Ro60, La, SmB, SmD, RNP-70k, RNP-A, RNP-C, CENP-C, Scl-70, Jo-1, ribosomal RNP and histones was investigated in 193 mothers of children with AV block by immunoblotting and ELISA. Autoantibody reactivity was detected in 48% (93/193) of the mothers of children with AV block. In autoantibody-positive mothers, the vast majority, 95% (88/93), had antibodies against Ro52, while 63% (59/93) had autoantibodies to Ro60 and 58% (54/93) had autoantibodies to La. In addition, 13% (12/93) of the autoantibody-positive mothers had antibodies to other investigated antigens besides Ro52, Ro60 and La, and of these anti-histone antibodies were most commonly represented, detected in 8% (7/93) of the mothers. In conclusion, this Swedish population-based study confirms that maternal autoantibodies may associate with heart block in the child. Further, our data demonstrate a dominant role of Ro52 antibodies in association with AV block.
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| 10. |
- Abrahamsson, Kate, 1959, et al.
(författare)
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Transient reduction of human left ventricular mass in carnitine depletion induced by antibiotics containing pivalic acid.
- 1995
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Ingår i: British heart journal. - : BMJ. - 0007-0769. ; 74:6, s. 656-9
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Tidskriftsartikel (refereegranskat)abstract
- To study the effect of induced carnitine depletion on myocardial structure and function.7 healthy adult volunteers given 1200 mg pivmecillinam per day for 7-8 weeks were studied by echocardiography before and after 7-8 weeks of treatment and a 15 months follow up after the treatment period.Teaching hospital.Carnitine concentration in serum, urine, and muscle and echocardiographic measurements.After 7-8 weeks of treatment the median free serum carnitine concentration was reduced to 7% and the median total muscle carnitine concentration to 46% of the pretreatment levels. The median diastolic interventricular septum thickness decreased by 14% (mean 26%, P = 0.028) and the median left ventricular mass by 10% (mean 20%, P = 0.018). Fifteen months later these dimensions had increased but not completely returned to pretreatment values.Extended treatment with pivalic acid containing antibiotics causes carnitine depletion which may lead to changes in cardiac structure.
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