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Professor Oliver Ileperuma Delivers the Professorial Lecture

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Professor Oliver Amarasena Ileperuma graduated from the University of Ceylon in 1970 with a Second Class Upper Division honors degree in Chemistry. He joined the University of Peradeniya in 1970 as an Assistant Lecturer and in 1972, he received a Fulbright Hays fellowship for graduate studies in the USA. In 1975, he received the C. S. Marvel fellowship for academic excellence from the University of Arizona, USA.  He obtained his Ph.D from the University of Arizona, USA in 1976 in the area of Inorganic chemistry.

After returning to Sri Lanka in 1976, he initiated his independent research work on coordination chemistry followed by work on photocatalysis on semiconductors as a lecturer in chemistry. This work was followed by research on dye-sensitized solar cells, particularly in the use of gel polymer electrolytes in dye-sensitized solar cells. Simultaneously he has carried out work related to environmental pollution issues such as air pollution, water pollution and the chronic kidney disease in the north-central province. In 1982, he was promoted to senior Lecturer and later as Associate Professor in 1989. In 1991, he received an EEC post-doctoral fellowship to work at the University of Southampton, UK. In 1993, he was promoted as professor of inorganic chemistry and was promoted to Senior Professor in 1999.

In addition to the above academic positions at the University of Peradeniya, Prof. Ileperuma has also served as a Senior Research Associate at the National Institute of Fundamental studies Institute of Fundamental Studies (former Institute of Fundamental Studies) from 1994 to 1996.

From 2004 to 2006, he served as the Head of the Department of Chemistry, University of Peradeniya and served as the Dean/Faculty of Science during 2006-2007.

Further, he worked as a visiting research Professor at the Research Institute of Electronics, Shizuoka University, Japan during the period 2007-2008.

He has completed four decades of service to the University of Peradeniya before his retirement in 2013.

He is a fellow of Institute of Chemistry, Ceylon and a Chartered Chemist (CChem) and a member of several professional bodies in Sri Lanka such as Sri Lanka Association for the Advancement of Science and the National Academy of Sciences.

He is a recipient of several national and international research grants and got several honors and awards as well. The Devanathan memorial award for research excellence in Physical Chemistry and related areas awarded by the Institute of Chemistry in 1994, The Hiran Tillekeratne award for best outstanding postgraduate research awarded by the University Grants Commission in 2001, and  the award for the best researcher in the Physical sciences in 2007 awarded by the committee of Vice Chancellors and Directors.

He has published over 78 research papers in International journals, 55 communications at meetings, 9 as editor of proceedings of International conferences, and 12 textbooks. He has successfully supervised 16 postgraduate students in many different areas of chemistry ranging from Studies on solid state solar cells fabricated from dye-sensitized semiconductor nanostructures, air pollution and acid rain monitoring, transboundary pollution, and

upervised 16 postgraduate students in many different areas of chemistry ranging from Studies on solid state solar cells fabricated from dye-sensitized semiconductor nanostructures, air pollution and acid rain monitoring, transboundary pollution, and Geo-environmental factors responsible for Chronic Renal Failure in Sri Lanka.

Abstract of the Professorial Lecture 

From Coordination Chemistry to Semiconductor Photochemistry and Solar Energy Conversion: A Voyage through Four Decades of Research

Semiconductor photocatalysis is important owing to the global energy crisis and using solar energy to carry out important reactions such as water splitting, degradation of pollutants, nitrogen fixation and solar cells has distinct advantages. Water splitting reaction on ferric oxide was first discovered during this work on irradiated nanoparticle. It was found that compared to crystalline iron oxide, band gap increases by 0.28 eV for 40 nm particles for nano ferric oxide taking it above the redox level for hydrogen reduction. In addition, oxidative nitrogen fixation to nitrate on irradiated TiO2 and hydrous ferric oxide was also discovered. More recently, water splitting on an infra-red active novel nanocomposite photocatalyst comprised of Ag2O/TiO2 was discovered. This observation can be attributed to the presence of sub-energy levels due to Ag2O within the band gap of TiO2.

Dye-sensitized solar cells are been extensively studied as a substitute to the more expensive and technologically complex silicon solar cells. However, the use of an organic liquid as the electrolyte severely limits its large-scale applications. In order to overcome this problem, polymer based gel electrolytes have been developed which showed slightly lower efficiencies (~7.5%) but with considerable stability suitable for large area solar cells. Polyacrylonitrile along with plasticizers ethylene carbonate and propylene carbonate can be easily converted to a gel which can then be hot pressed between the two electrodes of a solar cell. The use of such gel electrolytes has been extended to TiO2sensitised with organic dyes such as indoline D-149. The

I/I3ratio for optimal activity was found to be 1.50 M:0.05 M compared to 0.50 M:0.05 M  for the liquid electrolyte. Higher concentrations of Imay promote Grotthus type of mechanism through triiodide ion chains. Pore filling using the standard liquid electrolyte prior to hot pressing the gel electrolytes enhanced the efficiency from 5.2% to 8.4%, which is quite close to the 9.8% efficiency obtained for the standard liquid electrolyte. More recently, a polymer free gel electrolyte was prepared using fumed silica as the gelling agent. This had an efficiency of 7.5% and represents a more stable form suitable for long term applications of this type of solar cell.

Research carried out on the air quality of Kandy indicated that pollutant levels are 2-3 times more than the corresponding values of Colombo. Criteria pollutants in Kandy exceeded the air quality standards on about 40% of the occasions. Monthly variation of pollutants indicated that the pollutant levels are higher during the North-East monsoon owing to transboundary air pollution. Monitoring of acid rain in seven provinces except the North and the East indicate that acid rain occurs in the hill country and in the Anuradhapura district, particularly during the North-East monsoonal period. Computer modeling of future acidic depositions indicate that the highest acidic depositions will occur in Kandy followed by Jaffna again due to transboundary air pollution.

Chronic kidney disease of unknown etiology (CKDu) in the North-Central and Uva provinces has received considerable attention recently and studies carried out on the geographic distribution of this disease show that it is positively correlated to the fluoride distribution. Fluoride is a nephrotoxic element and its intake is further enhanced by the formation of aluminofluoride complexes when high fluoride water is stored or used for cooking in sub-standard aluminium utensils. It was also found that skeletal fluorosis patients all have CKDu. Providing purified water to such patients reverses the adverse effects of skeletal fluorosis with a concomitant improvement of kidney function.