| 1. |
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| 2. |
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| 3. |
- Bandara, Tmwj, et al.
(author)
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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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In: Journal of Materials Science-Materials in Electronics. - 0957-4522. ; 34:28
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Journal article (peer-reviewed)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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| 4. |
- Bandara, T M W J, 1968, et al.
(author)
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Characterization of poly (vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) nanofiber membrane based quasi solid electrolytes and their application in a dye sensitized solar cell
- 2018
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In: Electrochimica Acta. - : Elsevier BV. - 0013-4686. ; 266, s. 276-283
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Journal article (peer-reviewed)abstract
- The electrolyte plays a major role in dye sensitized solar cells (DSSCs). In this work a quasi-solid state (gel) electrolyte has been formed by incorporating a liquid electrolyte made with KI dissolved in ethylene carbonate (EC) and propylene carbonate (PC) co-solvent in poly (vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) co-polymer nanofiber membrane prepared by electrospinning. SEM images of the electrolyte membrane showed the formation of a three-dimensional network of polymer nanofibers with diameters between 100 and 300 nm and an average membrane thickness of 14 mu m. The electrolyte was characterized by FTIR and differential scanning calorimetry (DSC) measurements. The DSSCs fabricated with this electrolyte were characterized by current-voltage and Electrochemical Impedance Spectroscopy (EIS) measurements. DSC thermograms revealed that the crystallinity of the PVdF-HFP nanofiber is 14% lower than that of the pure PVdF-HFP polymer while the FTIR spectra showed a reduced polymer-polymer interaction in the nano fiber based gel electrolyte. The DSSCs fabricated with nanofiber based gel electrolyte showed an energy conversion efficiency of 5.36% under 1.5 a. m. solar irradiation, whereas the efficiency of the DSSC made with the liquid electrolyte based cell was 6.01%. This shows the possibility of replacing the liquid electrolyte in DSSCs by electro-spun polymer nanofiber based gel electrolyte and thereby minimizing some major drawbacks associated with liquid electrolyte based solar cells while maintaining a reasonably high efficiency.
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| 5. |
- Bandara, T M W J, 1968, et al.
(author)
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Combined effect of alkaline cations and organic additives for iodide ion conducting gel polymer electrolytes to enhance efficiency in dye sensitized solar cells
- 2017
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In: Electrochimica Acta. - : Elsevier BV. - 0013-4686. ; 252, s. 208-214
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Journal article (peer-reviewed)abstract
- Iodide ion conducting electrolytes are intensively studied as effectual electrolytes for dye-sensitized solar cells (DSSCs). However, the nature and concentration of the counter-ion (cation) in the electrolyte exert a profound influence on the performance of the thin film meso-porous TiO2 based DSSCs. A series of gel electrolytes containing the alkaline iodides LiI, NaI, KI, RbI and CsI and polyacrylonitrile (PAN) were fabricated together with the non-volatile plasticizers ethylene carbonate (EC) and propylene carbonate (PC). A similar series was fabricated with the inclusions of performance enhancers (additives) tetrapropylammonium iodide (Pr4NI), the ionic liquid 1-methyl-3-propyl imidazolium iodide (MPII) and 4-tert-butylpyridine (4TBP). The ionic conductivity of the electrolytes was studied in order to investigate its dependence on the nature of the alkaline cation in presence or absence of additives. The conductivities were higher for the electrolytes with the larger cations, namely K+, Rb+ and Cs+. A significant conductivity enhancement was observed in presence of the additives, and this effect was especially noticeable for samples with the smaller cations. The highest conductivity for electrolytes with additives, 3.96 mS cm(-1) at 25 degrees C, is exhibited by KI containing samples. (C) 2017 Elsevier Ltd. All rights reserved.
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| 6. |
- 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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| 7. |
- Bandara, T M W J, 1968, et al.
(author)
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Dependence of solar cell performance on the nature of alkaline counterion in gel polymer electrolytes containing binary iodides
- 2017
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In: Journal of Solid State Electrochemistry. - : Springer Science and Business Media LLC. - 1432-8488 .- 1433-0768. ; 21:6, s. 1571-1578
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Journal article (peer-reviewed)abstract
- Performance of dye-sensitized nano-crystalline TiO2 thin film-based photo-electrochemical solar cells (PECSCs) containing gel polymer electrolytes is largely governed by the nature of the cation in the electrolyte. Dependence of the photovoltaic performance in these quasi-solid state PECSCs on the alkaline cation size has already been investigated for single cation iodide salt-based electrolytes. The present study reports the ionic conductivity dependence on the nature of alkaline cations (counterion) in a gel polymer electrolyte based on binary iodides. Polyacrylonitrile-based gel polymer electrolyte series containing binary iodide salts is prepared using one of the alkaline iodides (LiI, NaI, KI, RbI, and CsI) and tetrapropylammonium iodide (Pr4NI). All the electrolytes based on binary salts have shown conductivity enhancement compared to their single cation counterparts. When combined with Pr4NI, each of the Li+, Na+, K+, Rb+, and Cs+ cation containing iodide salts incorporated in the gel electrolytes has shown a room temperature conductivity enhancement of 85.59, 12.03, 12.71, 20.77, and 15.36%, respectively. The conductivities of gel electrolytes containing binary iodide systems with Pr4NI and KI/RbI/CsI are higher and have shown values of 3.28, 3.43, and 3.23 mS cm(-1), respectively at room temperature. The influence of the nature of counterions on the performance of quasi-solid state dye-sensitized solar cells is investigated by assembling two series of cells. All the binary cationic solar cells have shown more or less enhancements of open circuit voltage, short circuit current density, fill factor, and efficiency compared to their single cation counterparts. This work highlights the importance of employing binary cations (a large and a small) in electrolytes intended for quasi-solid state solar cells. The percentage of energy conversion efficiency enhancement shown for the PECSCs made with electrolytes containing Pr4NI along with Li+, Na+, K+, Rb+, and Cs+ iodides is 260.27, 133.65, 65.27, 25.32, and 8.36%, respectively. The highest efficiency of 4.93% is shown by the solar cell containing KI and Pr4NI. However, the highest enhancements of ionic conductivity as well as the energy conversion efficiency were exhibited by the PECSC made with Li+-containing binary cationic electrolyte.
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| 8. |
- Bandara, T M W J, 1968, et al.
(author)
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Diatom frustules enhancing the efficiency of gel polymer electrolyte based dye-sensitized solar cells with multilayer photoelectrodes
- 2020
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In: Nanoscale Advances. - : Royal Society of Chemistry (RSC). - 2516-0230. ; 2:1, s. 199-209
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Journal article (peer-reviewed)abstract
- The incorporation of nanostructures that improve light scattering and dye adsorption has been suggested for dye-sensitized solar cells (DSSCs), but the manufacture of photonic and nanostructured materials with the desired properties is not an easy task. In nature, however, the process of light-harvesting for photosynthesis has, in some cases, evolved structures with remarkable wavelength-sensitive light-trapping properties. The present work is focused on enhancing the efficiency of quasi solid-state DSSCs by capitalizing on the light trapping properties of diatom frustules since they provide complex 3-dimensional structures for scattering and trapping light. This study reports a promising approach to prepare TiO2 nanocrystal (14 nm) based photo-electrodes by utilizing the waveguiding and photon localization effects of nanostructured diatom frustules for enhancing light harvesting without deteriorating the electron conduction. Single and double-layered photo-electrodes were prepared with different frustule/nanocrystal combinations and conformations on transparent conductive oxide substrates. This study clearly reports impressive efficiency and short circuit current density enhancements of about 35% and 39%, respectively, due to the incorporation of diatom frustules extracted from a ubiquitous species. The SEM images obtained in this work reveal that the produced thin films had a remarkable surface coverage of evenly distributed frustules within the TiO2 nanoparticle layer. To the best of our knowledge, this study reports the first quasi solid-state DSSC based on a photo-electrode with incorporated bio-formed nanostructures.
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| 9. |
- 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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| 10. |
- Bandara, T M W J, 1968, et al.
(author)
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Effect of the alkaline cation size on the conductivity in gel polymer electrolytes and their influence on photo electrochemical solar cells
- 2016
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In: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 18:16, s. 10873-10881
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Journal article (peer-reviewed)abstract
- The nature and concentration of cationic species in the electrolyte exert a profound influence on the efficiency of nanocrystalline dye-sensitized solar cells (DSSCs). A series of DSSCs based on gel electrolytes containing five alkali iodide salts (LiI, NaI, KI, RbI and CsI) and polyacrylonitrile with plasticizers were fabricated and studied, in order to investigate the dependence of solar cell performance on the cation size. The ionic conductivity of electrolytes with relatively large cations, K+, Rb+ and Cs+, was higher and essentially constant, while for the electrolytes containing the two smaller cations, Na+ and Li+, the conductivity values were lower. The temperature dependence of conductivity in this series appears to follow the Vogel-Tamman-Fulcher equation. The sample containing the smallest cation shows the lowest conductivity and the highest activation energy of similar to 36.5 meV, while K+, Rb+ and Cs+ containing samples show an activation energy of similar to 30.5 meV. DSSCs based on the gel electrolyte and a TiO2 double layer with the N719 dye exhibited an enhancement in the open circuit voltage with increasing cation size. This can be attributed to the decrease in the recombination rate of electrons and to the conduction band shift resulting from cation adsorption by TiO2. The maximum efficiency value, 3.48%, was obtained for the CsI containing cell. The efficiencies shown in this study are lower compared to values reported in the literature, and this can be attributed to the use of a single salt and the absence of other additives, since the focus of the present study was to analyze the cation effect. The highest short circuit current density of 9.43 mA cm(-2) was shown by the RbI containing cell. The enhancement of the solar cell performance with increasing size of the cation is discussed in terms of the effect of the cations on the TiO2 anode and ion transport in the electrolyte. In liquid electrolyte based DSSCs, the short circuit current density has been reported to decrease with the increasing size of the cation. However, in this work, it follows an opposite trend highlighting a major difference between liquid and quasi-solid electrolytes on the solar cell performance.
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| 11. |
- Bandara, T M W J, 1968, et al.
(author)
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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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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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| 12. |
- 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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| 13. |
- Bandara, T M W J, 1968, et al.
(author)
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N719 and N3 dyes for quasi-solid state dye sensitized solar cells - A comparative study using polyacrylonitrile and CsI based electrolytes
- 2016
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In: Ceylon Journal of Science. - : Sri Lanka Journals Online (JOL). - 2513-230X .- 2513-2814. ; 45:2, s. 61-69
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Journal article (peer-reviewed)abstract
- Dye sensitized solar cells offer a low cost alternative technology for solar energy harvesting. However, there are long term stability issues connected with these cells due to the liquid electrolytes normally used. Gel or solid polymer electrolytes which do not contain volatile solvents have been used in this investigation in order to alleviate these problems. Two types of solar cells were assembled using a double layered TiO2 film sensitized with two types of dye sensitizers, namely N719 (Ruthenizer 535-bisTBA) and N3 (Ruthenizer 535) in order to compare their performance. Quasi-solid-state electrolytes based on PAN (polyacrylonitrile) as the host polymer and CsI as the iodide salt were prepared by incorporating ethylene carbonate (EC) and propylene carbonate (PC) as plasticizers. The conductivity of the electrolyte was further improved by adding tetrapropylammonium iodide (Pr4NI), 1-methyl 3-propyl imidazolium iodide (MPII) and 4-tert-butylpyridine (4TBP). The incorporation of these additives resulted in 17% enhancement in ionic conductivity. This improved electrolyte was used to fabricate the solar cells with N3 and N719 dyes. The efficiency of the N3 dye based solar cell was 3.85% whereas the efficiency of the N719 dye based solar cell was 4.14% representing a significant efficiency enhancement by 7.53% by the N719 dye. In addition, due to additives the solar cell efficiency has enhanced by 19% compared to the solar cell without any additive.
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| 14. |
- Bandara, T M W J, 1968, et al.
(author)
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Novel photo-voltaic device based on Bi_{1−x}La_xFeO_3 perovskite films with higher efficiency
- 2019
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In: Journal of Materials Science: Materials in Electronics. - : Springer Science and Business Media LLC. - 1573-482X .- 0957-4522. ; 30:2, s. 1654-1662
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Journal article (peer-reviewed)abstract
- Photovoltaic cells using polycrystalline La substituted bismuth iron oxide, Bi1−xLaxFeO3, (0.1 ≤ x ≤ 0.4), films as the light harvesting component were investigated in this work. A novel cell set-up utilizing a double layered TiO2 film as top contact and a thin layer of quasi-solid polymer electrolyte as back contact was used and a significant enhancement in cell efficiency was observed for assemblies based on x ≥ 0.2 samples, coincident with a structural transition of Bi1−xLaxFeO3 from ferroelectric to non-ferroelectric. The power conversion efficiency of the PV device was 0.13% for the cell with x = 0.2 at 1 sun irradiation. The short circuit current density for this La composition was 0.35 mA cm−2. A hysteretic behaviour was observed for higher La compositions when the scanning is from open-circuit (OP) to short-circuit (SC) which may be attributed to polarization effects. The results at x ≥ 0.2 show an improved performance with respect to BiFeO3 based systems, suggesting the stabilization of the non-ferroelectric crystal structure leads either to a more efficient separation of photo-generated electron–hole pairs and/or enhanced charge transport. The findings represent a step towards the realisation of facile to fabricate, inorganic solid state photovoltaic devices.
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| 15. |
- Bandara, T M W J, 1968, et al.
(author)
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Performance enhancers for gel polymer electrolytes based on LiI and RbI for quasi-solid-state dye sensitized solar cells
- 2016
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In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 6:105, s. 103683-103691
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Journal article (peer-reviewed)abstract
- In this study, the effect of additives (enhancers) on efficiency enhancement in dye sensitized solar cells (DSSCs) containing two series of gel polymer electrolytes, one based on LiI and the other based on RbI have been systematically studied. Polyacrylonitrile (PAN) was used as the host polymer while the performance enhancers used in each case were tetrapropylammoniumiodide (Pr4NI), the ionic liquid 1-methyl-3-propyl imidazolium iodide (MPII) and 4-tert-butylpyridine (4TBP) respectively. Appropriate amounts of the selected enhancers were incorporated one by one, in LiI based and RbI based gel electrolytes. The incorporation of Pr4NI and MPII led to an increase in conductivity of the electrolyte, while 4TBP showed a decrease in conductivity. The maximum conductivity of 3.85 mS cm(-1) at room temperature was shown by the RbI based-series while for the LiI based series the maximum conductivity was 2.95 mS cm(-1). Each of these electrolytes with respective additives was used to fabricate quasi-solid state DSSCs. For the DSSCs based on the LiI containing series, a significant short circuit current density (J(sc)) enhancement (161%) from 3.65 to 9.54 mA cm(-2) was observed due to the addition of Pr4NI. This J(sc) value further increased to 9.7 mA cm(-2) due to the addition of MPII and 4TBP. For the DSSCs with corresponding Rb based electrolytes with all three additives, the highest J(sc) value obtained was 11.5 mA cm(-2). The incorporation of the three additives Pr4NI, MPII and 4TBP collectively enhanced the open circuit voltages and the efficiencies of both LiI and RbI containing quasi-solid state DSSCs. Another important finding from this work is that rarely used RbI containing electrolytes exhibit superior DSSC performance compared to more frequently used LiI based electrolytes. Hence, RbI appears to be a better candidate compared to LiI to fabricate gel polymer electrolytes for DSSCs in general. The three additives have contributed to a remarkable efficiency enchantment in DSSCs by 449.3% for the LiI based electrolyte and by 35.7% for the RbI based electrolyte.
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| 16. |
- 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
-
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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| 17. |
- Bandara, T M W J, 1968, et al.
(author)
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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
-
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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| 18. |
- Bandara, Tmwj, et al.
(author)
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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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In: Optical Materials. - 0925-3467. ; 146
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Journal article (peer-reviewed)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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| 19. |
- Bandara, Tmwj, et al.
(author)
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Novel photo-voltaic device based on Bi1-xLaxFeO3 perovskite films with higher efficiency
- 2019
-
In: Journal of Materials Science-Materials in Electronics. - : Springer Science and Business Media LLC. - 0957-4522 .- 1573-482X. ; 30:2, s. 1654-1662
-
Journal article (peer-reviewed)abstract
- Photovoltaic cells using polycrystalline La substituted bismuth iron oxide, Bi1-xLaxFeO3, (0.1x0.4), films as the light harvesting component were investigated in this work. A novel cell set-up utilizing a double layered TiO2 film as top contact and a thin layer of quasi-solid polymer electrolyte as back contact was used and a significant enhancement in cell efficiency was observed for assemblies based on x0.2 samples, coincident with a structural transition of Bi1-xLaxFeO3 from ferroelectric to non-ferroelectric. The power conversion efficiency of the PV device was 0.13% for the cell with x=0.2at 1 sun irradiation. The short circuit current density for this La composition was 0.35mAcm(-2). A hysteretic behaviour was observed for higher La compositions when the scanning is from open-circuit (OP) to short-circuit (SC) which may be attributed to polarization effects. The results at x0.2 show an improved performance with respect to BiFeO3 based systems, suggesting the stabilization of the non-ferroelectric crystal structure leads either to a more efficient separation of photo-generated electron-hole pairs and/or enhanced charge transport. The findings represent a step towards the realisation of facile to fabricate, inorganic solid state photovoltaic devices.
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| 20. |
- Bertilsson, S., et al.
(author)
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Lithium-ion battery electrolyte emissions analyzed by coupled thermogravimetric/Fourier-transform infrared spectroscopy
- 2017
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In: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 365, s. 446-455
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Journal article (peer-reviewed)abstract
- In the last few years the use of Li-ion batteries has increased rapidly, powering small as well as large applications, from electronic devices to power storage facilities. The Li-ion battery has, however, several safety issues regarding occasional overheating and subsequent thermal runaway. During such episodes, gas emissions from the electrolyte are of special concern because of their toxicity, flammability and the risk for gas explosion. In this work, the emissions from heated typical electrolyte components as well as from commonly used electrolytes are characterized using FT-IR spectroscopy and FT-IR coupled with thermogravimetric (TG) analysis, when heating up to 650 degrees C. The study includes the solvents EC, PC, DEC, DMC and EA in various single, binary and ternary mixtures with and without the LiPF6 salt, a commercially available electrolyte, (LP71), containing EC, DEC, DMC and LiPF6 as well as extracted electrolyte from a commercial 6.8 Ah Li-ion cell. Upon thermal heating, emissions of organic compounds and of the toxic decomposition products hydrogen fluoride (HF) and phosphoryl fluoride (POF3) were detected. The electrolyte and its components have also been extensively analyzed by means of infrared spectroscopy for identification purposes.
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| 21. |
- Bettucci, Ottavia, et al.
(author)
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Organic dye-sensitized solar cells containing alkaline iodide-based gel polymer electrolytes: Influence of cation size
- 2018
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In: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 20:2, s. 1276-1285
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Journal article (peer-reviewed)abstract
- The electrolyte used in dye-sensitized solar cells (DSSCs) plays a key role in the process of current generation, and hence the analysis of charge-transfer mechanisms both in its bulk and at its interfaces with other materials is of fundamental importance. Because of solvent confinement, gel polymer electrolytes are more practical and convenient to use with respect to liquid electrolytes, but in-depth studies are still necessary to optimize their performances. In this work, gel polymer electrolytes of general formulation polyacrylonitrile (PAN)/ethylene carbonate (EC)/propylene carbonate (PC)/MI, where M + is a cation in the alkaline series Li-Cs, were prepared and used in DSSCs. Their ionic conductivities were determined by impedance analysis, and their temperature dependence showed Arrhenius behavior within the experimental window. FT-IR studies of the electrolytes confirmed the prevalence of EC coordination around the cations. Photo-anodes were prepared by adsorbing organic sensitizer D35 on nanocrystalline TiO 2 thin films, and employed to build DSSCs with the gel electrolytes. Nanosecond transient spectroscopy results indicated a slightly faster dye regeneration process in the presence of large cations (Cs + , Rb + ). Moreover, a negative shift of TiO 2 flat-band potential with the decreasing charge density of the cations (increasing size) was observed through Mott-Schottky analysis. In general, results indicate that cell efficiencies are mostly governed by photocurrent values, in turn depending on the conductivity increase with cation size. Accordingly, the best result was obtained with the Cs + -containing cell, although in this case a slight reduction of photovoltage compared to Rb + was observed.
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| 22. |
- 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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| 23. |
- Dissanayake, M. A. K. L., et al.
(author)
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High-efficiency dye-sensitized solar cells fabricated with electrospun PVdF-HFP polymer nanofibre-based gel electrolytes
- 2023
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In: Bulletin of Materials Science. - 0973-7669 .- 0250-4707. ; 46:2
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Journal article (peer-reviewed)abstract
- Poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) electrospun polymer nanofibre-based quasi-solid or gel electrolytes were successfully fabricated by incorporating a liquid electrolyte within the nanofibre membrane. The dye-sensitized solar cells (DSSCs) fabricated with gel and with liquid electrolyte were characterized by photocurrent–voltage measurements and electrochemical impedance spectroscopy measurements. The maximum efficiency (η) of 6.79% was observed for the DSSC fabricated with optimized nanofibre membrane thickness, corresponding to 4 min of electrospinning time. The optimized PVdF-HFP nanofibre gel electrolyte shows an ionic conductivity of 7.16 × 10−3 S cm–1 at 25°C, while the corresponding liquid electrolyte exhibits an ionic conductivity of 11.69 × 10–3 S cm–1 at the same temperature. The open circuit voltage (Voc), short circuit current density (Jsc) and fill factor were recorded as 801.40 mV, 12.70 mA cm–2, and 66.67%, respectively, at an incident light intensity of 100 mW cm–2 with a 1.5 AM filter. The nanofibre gel electrolyte-based cell showed an efficiency of 6.79%, whereas the efficiency of the conventional liquid electrolyte-based cell was 7.28% under the same conditions. Furthermore, nanofibre gel electrolyte-based cells exhibited better stability, maintaining 85.40% of initial efficiency after 120 h. These results show that the optimized, polymer nanofibre-based gel electrolyte can be used successfully to replace the liquid electrolyte in DSSCs without much loss of efficiency but improving the stability while minimizing most of the drawbacks associated with liquid electrolytes.
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| 24. |
- Dissanayake, M. A. K. L., et al.
(author)
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Highly efficient, PbS:Hg quantum dot-sensitized, plasmonic solar cells with TiO2 triple-layer photoanode
- 2019
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In: Journal of Solid State Electrochemistry. - : Springer Science and Business Media LLC. - 1433-0768 .- 1432-8488. ; 23:6, s. 1787-1794
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Journal article (peer-reviewed)abstract
- Highly efficient, PbS:Hg quantum dot-sensitized, plasmonic solar cells with TiO2 triple-layer photoanode were fabricated by successive ionic layer adsorption and reaction (SILAR) method. These nanostructured photoanodes were characterized by optical and morphological techniques and the solar cells were characterized by optical and electrical techniques. The light absorption by the photoanode was enhanced by effective light scattering process using a triple-layer TiO2 nanostructure, fabricated with a TiO2 nanofiber layer sandwiched between two TiO2 nanoparticle layers. The best plasmon-enhanced quantum dot-sensitized solar cell showed an efficiency of 5.41% with short circuit current density of 18.02mAcm(-2) and open-circuit voltage of 679.83mV. The overall efficiency and photocurrent density of the Q-dot-sensitized solar cell are enhanced by 15.84% and 38.83% respectively due to the plasmonic effect. The enhanced efficiency appears to be due to the improved short circuit current density by increased light absorption by the triple-layered photoanode nanostructure as well as by the localized surface plasmon resonance (LSPR) effect of the plasmonic gold nanoparticles. This is the first report on plasmon-enhanced, triple-layered TiO2 photoanode sensitized with PbS:Hg Q-dots.
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| 25. |
- Dissanayake, Makl, et al.
(author)
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Optimizing the size and amount of CdS quantum dots for efficiency enhancement in CdS/N719 co-sensitized solar cells
- 2022
-
In: Physica E-Low-Dimensional Systems & Nanostructures. - : Elsevier BV. - 1386-9477. ; 144
-
Journal article (peer-reviewed)abstract
- Co-sensitization of TiO2 photoanodes in solar cells with Ruthenium dye and quantum dots offer better photovoltaic performance compared to the sensitization by the dye only. In the present study, TiO2 nanostructured photoanode was co-sensitized with CdS quantum dots and N719 dye. CdS quantum dots were deposited using successive ionic layer adsorption and reaction (SILAR). A suitable thin ZnS interfacial layer has been introduced between two sensitizers to prevent the corrosion of CdS quantum dots by the iodide-based liquid electrolyte. In order to get the highest efficiency, the number of SILAR cycles for CdS quantum dot deposition has been optimized. A power conversion efficiency of 6.79% with short-circuit current density of 15.55 mA cm-2 and open circuit voltage of 764.5 mV have been obtained for the co-sensitized solar cell made with TiO2/CdS/ZnS/N719 co-sensitized photoanode under the illumination of 100 mW cm-2 with AM 1.5 spectral filter. Efficiency and short-circuit current density of the solar cell have been enhanced by 11.31% and 6.58% respectively due to the co-sensitization. The optimized co-sensitized solar cell shows a higher incident photon to current conversion efficiency and a reduced electron recombination compared to the solar cell with dye-sensitized photoanode. Higher recombination resistance and longer electron lifetime of the solar cell with CdS/ZnS/N719 co-sensitized TiO2 photoanode have contributed to the increased short circuit current and open circuit voltage leading to the enhanced efficiency of 6.79% which is among the highest for a co-sensitized dye sensitized solar cell.
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| 26. |
- Dissanayake, Makl, et al.
(author)
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Polyaniline (PANI) mediated cation trapping effect on ionic conductivity enhancement in poly(ethylene oxide) based solid polymer electrolytes with application in solid state dye sensitized solar cells
- 2020
-
In: Reactive & Functional Polymers. - : Elsevier BV. - 1381-5148. ; 155
-
Journal article (peer-reviewed)abstract
- The ionic conductivity enhancement in solid polymer electrolytes due to introduction of polyaniline (PANI) conducting polymer is demonstrated using poly(ethylene oxide) (PEO) based solid polymer electrolyte comprising tertapropylamonium iodide (Pr4NI) and iodine (I-2). The electrolyte with optimized composition has been characterized by ionic conductivity measurements, DC polarization test, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Differential Scanning Calorimetry (DSC). About eight-fold increase in the ionic conductivity from 9.33 x 10(-6) Scm(-1) to 8.61 x 10(-5) Scm(-1) at room temperature was obtained by the addition of 1.5 wt% of PANI to the PEO solid polymer host. FTIR measurements suggest that Pr4N+ cations are able to coordinate not only with oxygen atoms of PEO, but also with nitrogen atoms of the PANI polymer effectively immobilizing or "trapping" the bulky Pr4N+ cations and promoting ionic dissociation. DSC studies show that PANI, also acting as a plasticizer, reduces the crystallinity of PEO and lower it's melting temperature. The DC polarization tests confirmed the increased iodide ion conductivity evidently mediated by PANI due to the combined effect of cation trapping and plasticizing. Solid state dye sensitized solar cells fabricated with optimized electrolyte composition incorporating PANI exhibited the highest energy con version efficiency of 5.01% compared to 3.52% for the DSSC without PANI.
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| 27. |
- Dissanayake, Makl, et al.
(author)
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Solid-state solar cells co-sensitized with PbS/CdS quantum dots and N719 dye and based on solid polymer electrolyte with binary cations and nanofillers
- 2021
-
In: Journal of Photochemistry and Photobiology a-Chemistry. - : Elsevier BV. - 1010-6030. ; 405
-
Journal article (peer-reviewed)abstract
- Co-sensitized solar cells have gained more attention due to the ability of energy conversion process by absorbing photons from wide range of the solar spectrum including visible and near-infrared region. TiO2 electrodes were co-sensitized with PbS/CdS core-shell quantum dots and N719 dye. PbS/CdS/N719 dye-sensitized solar cells were fabricated with poly(ethylene oxide) based solid polymer electrolyte consisting iodide/triiodide redox couple. The iodide ion conductivity of the electrolyte was enhanced by incorporating a binary iodide salt mixture of different size cations, tetrapropylammonium iodide and potassium iodide. The performance of the solar cell was further enhanced by the incorporating TiO2 P90 nanofiller in the electrolyte. The best solid-state solar cell showed a significantly higher efficiency of 4.41 % with a short-circuit current density of 8.41 mA cm(-2), open circuit voltage of 748.3 mV and a high fill factor of 70.16 % under the simulated light of 100 mW cm(-2) with AM 1.5 filter. This is the first report describing the efficiency enhancement in a solid-state dye sensitized solar cell based on a solid polymer electrolyte incorporating a binary cation iodide salt and TiO2 nanofiller and a photoanode co-sensitized with PbS/CdS quantum dots and N719 dye demonstrating the cumulative effect by the mixed cation effect and co-sensitization.
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| 28. |
- Furlani, Maurizio, 1958, et al.
(author)
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Annealing protocols for pyrrolidinium bis(trifluoromethylsulfonyl)imide type ionic liquids
- 2011
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In: Electrochimica Acta. - : Elsevier BV. - 0013-4686. ; 57, s. 220-227
-
Journal article (peer-reviewed)abstract
- The phase transitions in ionic liquids (ILs) of the N-alkyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR(1A)TFSI) family show a common pattern, which implies a typical and characteristic crystal packing. Many of these features are also observed for the N-alkyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide (PIP(1A)TFSI) family. Here we report the thermal behavior of some ILs of the PYR(1A)TFSI and PIP(1A)TFSI families and a few others having different anions. The thermal history was found to decide which phases will appear and, therefore, specific protocols were defined to obtain the desired phases in a reasonable amount of time. (C) 2011 Elsevier Ltd. All rights reserved.
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| 29. |
- Furlani, Maurizio, 1958, et al.
(author)
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Concentration dependence of ionic relaxation in lithium doped polymer electrolytes
- 2010
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In: Journal of Non-Crystalline Solids. - : Elsevier BV. - 0022-3093 .- 1873-4812. ; 356:11-17, s. 710-714
-
Journal article (peer-reviewed)abstract
- A detailed impedance spectroscopy study at ambient temperature was carried out on polymer electrolytes based on low molecular weight poly(ethylene oxide) 400, poly(propylene oxide) 400 and a random copolymer of molecular weight 600, to which were added LiN(CF3SO2)(2) (LiTFSI) salt. The ionic conductivity exhibits a maximum at intermediate salt concentrations and is significantly higher for poly(ethylene oxide) and the copolymer. A dielectric relaxation was found in a frequency region above the one, where the ion conductivity dominates the dielectric response, and below the region of the relaxations of the polymer host. The relaxation strength scales with ion concentration, as appropriate for an ion pair relaxation in systems above the glass transition. The frequency of this relaxation, multiplied by the relaxation strength, has been found to be proportional to the ion conductivity, and the relaxation has therefore been assigned to short-range ionic motion in the polymer. It exhibits characteristics similar to conductivity relaxations in inorganic solid ion conductors, and is considered to be due to the same species that give rise to the ion conductivity. (C) 2010 Elsevier B.V. All rights reserved.
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| 30. |
- Larsson, Carl Fredrik, 1980, et al.
(author)
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Gas explosions and thermal runaways during external heating abuse of commercial lithium-ion graphite-LiCoO2 cells at different levels of ageing
- 2018
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In: Journal of Power Sources. - : Elsevier BV. - 0378-7753. ; 373, s. 220-231
-
Journal article (peer-reviewed)abstract
- Commercial 6.8 Ah lithium-ion cells with different ageing/status have been abused by external heating in an oven. Prior to the abuse test, selected cells were aged either by C/2 cycling up to 300 cycles or stored at 60 °C. Gas emissions were measured by FTIR and three separate vents were identified, two well before the thermal runaway while the third occurred simultaneously with the thermal runaway releasing heavy smoke and gas. Emissions of toxic carbon monoxide (CO), hydrogen fluoride (HF) and phosphorous oxyfluoride (POF3) were detected in the third vent, regardless if there was a fire or not. All abused cells went into thermal runaway and emitted smoke and gas, the working cells also released flames as well as sparks. The dead cells were however less reactive but still underwent thermal runaway. For about half of the working cells, for all levels of cycle ageing, ignition of the accumulated battery released gases occurred about 15 s after the thermal runaway resulting in a gas explosion. The thermal runaway temperature, about 190 °C, varied somewhat for the different cell ageing/status where a weak local minimum was found for cells cycled between 100 and 200 times.
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| 31. |
- Loupe, Neili, et al.
(author)
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DFT - experimental IR spectroscopy of lithiated single ion conducting perfluorinated sulfonated ionomers: Ion induced polarization band broadening
- 2017
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In: Journal of Electroanalytical Chemistry. - : Elsevier BV. - 1572-6657. ; 800, s. 176-183
-
Journal article (peer-reviewed)abstract
- The impact of state of hydration and ion exchange on the exchange site local symmetry of Aquivion and Nafion perfluorinated sulfonated ionomers (PFSI) are probed by transmission IR spectroscopy.Hydrated PFSI-H membranes exhibit a pair of bands corresponding to a dissociated sulfonate exchange site with a local 3-fold axis of symmetry (C3V). C3V bands are supplanted by C1 bands (no local symmetry) corresponding to the sulfonic acid form of the exchange site. At intermediate states of hydration C3V and C1 bands co-exist. Hydrated PFSI-Li exhibits C3V bands. In contrast to PFSI-H, the PFSI-Li C3V bands persist throughout dehydration, with a final aggregate structure where each Li+ provides 1/3 of a charge per sulfonate oxygen with an overall C3V motif. The C3V band FWHM values progressively increase (hydrated PFSI-H
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| 32. |
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| 33. |
- Salve, Maruti V., et al.
(author)
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Highly Crystalline and Stoichiometric Growth of CdTe by Cost-Effective Hydrothermal Technique
- 2024
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In: JOURNAL OF ELECTRONIC MATERIALS. - 0361-5235 .- 1543-186X.
-
Journal article (peer-reviewed)abstract
- CdTe powder samples have been synthesized using a hydrothermal approach, employing cadmium acetate and tellurium dioxides as sources of Cd and Te, respectively. NaBH4 was utilized as the reducing agent, and double-distilled water was used as the solvent in the synthesis process. The effect of annealing on the synthesized samples was investigated. The samples have been characterized by x-ray powder diffraction, Raman spectroscopy, UV-Vis-NIR spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, and x-ray photoelectron spectroscopy. The electrical properties (current-voltage and capacitance-voltage) of the as-prepared and annealed CdTe pellets were investigated. These findings indicate that annealing can lead to improvements in crystallinity, crystallite size, and electrical conductance. This paper presents a simple, cost-effective, and versatile method for producing significant amounts of CdTe nanostructure powders with properties suitable for use in the fabrication of CdS/CdTe solar cells.
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| 34. |
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| 35. |
- Ukarande, Aparna, et al.
(author)
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Investigation of electrodeposited CdTe thin films for solar cell development
- 2023
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In: Journal of Materials Science: Materials in Electronics. - 1573-482X .- 0957-4522. ; 34:27
-
Journal article (peer-reviewed)abstract
- We report the growth of CdTe thin films using a wet-chemical electrochemical technique in an aqueous bath. The effect of bath temperature is investigated in detail on the various properties of the sample and the optoelectronic performance of the solar cell devices. A three-electrode technique was employed to deposit the samples at − 0.7 V concerning the Ag/AgCl reference electrode optimized by cyclic voltammetry measurements. The sample annealed at 450 °C for 20 min exhibited a polycrystalline cubic crystal structure of CdTe with an optical energy bandgap of ~ 1.45 eV. The Raman analysis reveals the growth of highly polycrystalline CdTe. All samples were highly compact and well-adherent to the substrate without pinholes. The annealed sample grown at a bath temperature of 50 °C exhibited a large globular grain size of ~ 1 μm. Furthermore, the stoichiometric (50:50) growth of Cd and Te was confirmed using EDAX for the sample grown at a bath temperature of 50 °C. A typical solar cell device, glass/FTO/CdS/CdTe/Au, was measured under dark and illuminated conditions with an input intensity of 100 mW/cm2 and showed a fill factor of ~ 50% and an efficiency of 2.65%. The solar cell parameters can be further improved by optimizing the surface treatment conditions using appropriate oxidizing and reducing reagents.
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| 36. |
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