Chemistry
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Item Electrodeposition of ZnS Thin Films by Complexing Agent‑Free Electrolyte Containing Sodium Thiosulfate as the Sulfur Precursor(Journal of Electronic Materials, 2021) Madhuwanthi, H.M.L.U.; Mahanama, G.D.K.; de Silva, D.S.M.Thin films of zinc sulphide (ZnS) were prepared by a facile, economical, and scalable electrochemical method as a buffer layer for a CdS/CdTe based solar cell. Herein, a three-electrode cell in a complexing agent-free electrolyte containing 0.1 mol/L Na2S2O3 and 0.1 mol/L ZnSO4 was employed for the deposition of ZnS. The electrodeposition conditions (temperature: 30°C, pH: 4.2, cathodic potential: −1.10 V and deposition time: 90 min) were identified to grow an ideal thin film of ZnS on fluorine-doped tin oxide (FTO)-coated glass substrate, applying moderate stirring of 60 rpm. In material characterization of heat-treated samples (300°C, 10 min), the optical absorption measurement depicted a direct energy bandgap of 3.64 eV with low light absorbance and a blueshift from bulk ZnS. Scanning electron microscopy and atomic force microscopy studies demonstrated the uniform distribution of ZnS grains over the FTO glass substrate, and x-ray diffraction analysis revealed an amorphous structural nature of ZnS. The charge carrier density and flat-band potential of the ZnS material were determined as 1.19 × 10− 19 cm− 3 and −0.59 V, respectively, by Mott–Schottky analysis.Item Is it possible to grow stable p-type CdS layers suitable for fabrication of electronic devices?(University of Malaya, Malaysia, 2013) Kiriarachchi, H.D.; Lamahewage, L.H.S.N.S.; Wickramasinghe, W.A.S.; de Silva, D.S.M.; Pathiratne, K.A.S.; Dharmadasa, I.M.CdS is a technologically important wide bandgap window material with some unique properties showing highest conversion efficiencies in thin film solar cells based on CdTe and CuInGaSe2 absorber materials. n-CdS/CdTe and n-CdS/CuInGaSe2 hetero-interfaces based solar cells have demonstrated 18.7% and 20.3% lab-scale solar cell efficiencies to date. Both these devices are fabricated based on n-type CdS window material. Recent work on graded bandgap devices using p-type AlGaAs window materials experimentally demonstrated highest Voc values of 1175 mV together with highest possible FF values ~0.85, and therefore if p-CdS can be grown, it provides another route to improve solar cell efficiencies and open doors for many other electronic devices. There are several attempts to grow Cu-doped p-CdS in the literature but the follow-up research work or devices based on p-CdS are scarce. In this research programme of solar energy materials development, using electrochemical growth method, p-type CdS was observed for certain layers. However, the stability of p-type CdS is found to be weak and these results are presented and discussed in this paper.Item Characterisation of spinifex (Triodia pungens) resin and fibres(Australasian Polymer Symposium, Cairns, QLD, Australia, 2009) de Silva, D.S.M.; Memmott, P.; Flutter, N.; Martin, D.Spinifex grasses have been largely ignored as a sustainable resource despite their widespread distribution throughout Australia. This project involves an in-depth study of the structure and properties of both the leaf and resinous components of various spinifex species and an investigation into the preparation and properties of Spinifex-based composite materials. The present work is comprised of two components, analysis of the resin and mechanical testing of various fibrous components. Resin of the soft Spinifex species (Triodia pungens) was extracted from the resinous stems of Spinifex grasses into methanol by soxhlet extraction. The dried extracts were chromatographed on silica gel, eluted with the solvent mixture of hexane and methanol with increasing polarity to give ten fractions. Resin was also extracted directly by soaking the resinous stems for 8 hours in hexane and methanol in order to study the polar and non-polar volatile compounds. The chemical composition of the fractions of the resin has been studied by means of GC-MS and LC-MS. ATR-FTIR spectroscopy was used to identify the functional groups present in the resin. Thermal analysis was also performed using DSC. GC-MS chromatograms revealedItem Selenium content in daily meals consumed by Sri Lankans-A preliminary study(Institute of Chemistry Ceylon, 2015) Kiridena, K.M.S.D.; de Silva, D.S.M.; Wimalasena, S.; Kannangara, A.T.; Weerarathna, H.P.Item Effect of stirring rate of the electrolyte on properties of electrodeposted CdS layers(International photovoltaic solar energy conference-Solar Asia, Pune, India, 2015) Atapattu, H.Y.R.; de Silva, D.S.M.; Pathiratne, K.A.S.; Dharmadasa, I.M.Item A comparison of performance between chemical bath deposited and electrochemical bath deposited CdS thin films in CdS/CdTe thin film solar cells(The U.S. Workshop on the Physics and Chemistry of II-VI materials, 2013) Pathiratne, K.A.S.; de Silva, D.S.M.; Kumarasinghe, K.D.M.S.P.K.; Dasanayake, B.S.; Colegrove, E.; Xin Zheng, R.D.; Sivananthan, S.Item A study on solution grown CdZnS as a window layer for solar applications(The U.S. Workshop on the Physics and Chemistry of II-VI materials, 2013) Dassanayake, B.S.; de Silva, D.S.M.; Pathiratne, K.A.S.; Colegrove, E.; Zheng, X.; Dhere, R.; Sivananthan, S.Item Fabrication of CdS (n-type) and CdTe (p-type) Thin Film Semiconductor Materials via Electrodeposition(Institute of Chemistry Ceylon, 2013) Sandaruwan, K.A.I.; Athukorala, P.S.; Pathiratne, K.A.S.; de Silva, D.S.M.; Dharmadasa, I.M.Item Selenium content in rice consumed by Sri Lankans(Institute of Chemistry Ceylon, 2013) Mahagama, S.; de Silva, D.S.M.; Wimalasena, S.Item Fabrication of CdS (p-type) thin film semiconductors via electrodepostion(Institute of Chemistry Ceylon, 2013) Kiriarachchi, H.D.; Lamahewage, H.S.N.S.; Pathiratne, K.A.S.; de Silva, D.S.M.; Dharmadasa, I.M.
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