Physics
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Item Electrodeposited Cu2O homojunction solar cells: Fabrication of a cell of high short circuit photocurrent(Elsevier, 2016) Wijesundera, R.P.; Gunawardhana, L.K.A.D.D.S.; Siripala, W.A Cu2O homojunction solar cell was fabricated using a consecutive electrodeposition method of deposition of an n-Cu2O film followed by a p-Cu2O film, in two different acetate baths. Both n-type and p-type film growth conditions were optimized separately to yield high photocurrents in a photoelctrochemical (PEC) cell. Further, the resulted bi-layer films were investigated in the PEC for the verification of the formation of the p-n homojunction. In addition, p-Cu2O film surfaces of the bi-layers were sulphided using Na2S and (NH4)2S in order to improve the photoresponse of the homojunction before depositing a Au film for the solar cell device. The structural, morphological and optoelectronic properties of the Cu2O films were investigated using X-ray diffraction (XRD), scanning electron micrographs (SEMs), dark and light current–voltage (I-V) and spectral response measurements and observed that the films are of good quality. Incident photon to current efficiency (IPCE) and I-V characteristics of the solar cell device demonstrated that the Cu2O homojunction can produce a high short circuit current density Jsc. However, the overall conversion efficiency of the device is low due to poor fill factor and Voc. The solar cell characteristics of the structure Ti/n-Cu2O/p-Cu2O/Au were Voc=287.0±0.1 mV, Jsc=12.4±0. 1 mA/cm2, FF=25±2% and η=0.89±0.02%, under AM 1.5 illumination. The record high Jsc value of the device demonstrates the prospect being improved the efficiency of Cu2O homojunction solar cells by optimizing deposition, pretreatment and post treatment processes.Item Potentiostatic electrodeposition of cuprous oxide thin films(Journal of the National Science Council of Sri Lanka, 1996) Perera, L.D.R.D.; Siripala, W.; de Silva, K.T.L.Current-potential scans were used to investigate the electrodeposition of coprous oxide thin films in an acetate bath. We found that a narrow potential domain, from OV vs SCE, is available for the potentiostatic electrodeposition of cuprous oxide thin films and extension of this domain towards more cathodic potentials will result in the co-deposition of copper. These results were further verified by the x-ray diffraction measurements on the thin films formed by the electrodeposition at various electrode potensials. Optical transmission studies revealed that electrodeposited cuprous oxide is a direct band gap semiconductor of 2.0 eV.Item Spectral responses of electrodeposited cuprous oxide thin film electrodes(Journal of the National Science Council of Sri Lanka, 1995) Siripala WPhotoresponse of the electrodeposited cuprous oxide thin film electrodes were investigated in a photoelectrochemical cell. Spectral response measurements reveal that a Schottky-type junction is formed at the junction between the substrate and cuprous oxide resulting in n-type and p-type photosignals in a photoelectrochemical cell. The electrodeposited cuprous oxide is an n-type semiconductor.