Sensors, Electrochemical Power Devices and Materials

About the group

Sensors, Electrochemical Power Devices and Materials Research Group is a newly formed research group in the Faculty of Applied Sciences and currently focusing on Sensors, Electrochemical Power Devices and Materials. The group is devoted to enhance the research contextual of the undergraduates, postgraduates and the training of scientist to the future in understanding of sensors and materials, electrochemical power devices and solar energy materials.

Group members

• Dr. H. N. M. Sarangika (Senior Lecturer Grade II in Physics)
• Dr. H. Y. R. Atapattu (Temporary Lecturer in Physics)
• Ms. W. G. M. D. Karunarathne (Temporary Demonstrator in Physics)

Areas of Focus

Sensors and materials

In recent decades the sensing technology has been widely explored and utilized for gas detection. Owing to the different applicability and innate limitations of different gas sensing technologies, researchers have been working on different scenarios with enhanced gas sensor calibration.

Gas sensing technology has become more significant because of its widespread and common applications in the areas of industrial production (e.g., CH4 detection in mines), automotive industry (e.g., detection of polluting gases from vehicles), medical applications (e.g., electronic noses simulating the human olfactory system), indoor air quality supervision (e.g., detection of carbon monoxide) and environmental studies (e.g., greenhouse gas monitoring). In recent times, there is an increasing interest in finding nanostructured materials in order to develop high performance solid-state gas sensors for environmental monitoring, home safety and chemical controlling. The gas sensing devices based on inorganic materials namely metal sulfide and metal oxide semiconductors, which works on principle of the change in conductivity with interaction of gas molecules. These sensor materials typically maintain a leading role in the gas sensing technology owing their high sensitivity, low cost, small dimensions and simple integration.

In this project our focus is to develop the semiconductor nanomaterials namely; ZnS, ZnO and CdS via the techniques of electrodeposition and/or precipitate method & spin coating for O2, NO2, NH3, CH4 and LP gas sensing. It is expected to enhance the sensitivity of the materials by controlling the properties of the nanomaterials grown.

Electrochemical power devices

It is predicted that among the top ten problems faced by the humans in the next decade would be the energy crises due to the depletion of the conventional energy sources like fossil fuels. Therefore, supply of energy will be the main challenge for maintaining a comfortable standing of living. Conventional energy sources based on fossil fuels are limited for supplying the needed for the modern world. Frequent use of fossil fuels also causes the rise of current level of CO2 in the atmosphere leading to environmental pollution. Therefore, finding alternative and environmental friendly renewable energy sources, developing less energy consuming technologies and efficient methods for storage of energy are being widely discussed in the scientific community.

Among the sources of renewable energy, the solar energy considered to be the most promising. In recent years technologies called electrochromism have attracted much attention due to their potential practical applications in everyday life with low power consumption. Rechargeable battery technology is considered as another CO2 emission free device for energy supply and storage.

The research presents in this project focuses on an investigation of the use of low cost TiO2 in three different electrochemical devices; Electrochromic devices, rechargeable Mg batteries and dye sensitized solar cells.

Solar energy materials

With the dawn of the industrial revolution, the global energy consumption has increased rapidly and as a consequence, the cost of production of energy and environmental pollution associated with it have increased exponentially leading to an energy crisis in the world. Hence this increasing demand of energy and limitations of currently dominant energy sources including fossil fuels, remind us the necessity of renewable and sustainable alternatives to energy sources in order to diminish the catastrophe in energy. However, amid various existing technologies, photovoltaics (PV) are the most promising and cleanest technology that can be used to overcome the current issue in the energy sector.

Sri Lanka being a developing country, with no non-renewable energy sources feels the energy crisis more than that felt by developed countries. However, the country is not using all its non-renewable energy sources at its optimum height and with right level of efficiency. Fortunately, Sri Lanka is blessed with plenty of unlimited free sun light and it can meet a major portion of the energy demand in the country if it is used effectively in PV devices that convert solar energy directly into electricity. The electrical energy so produced can be used in small scale as well as large scale devices and applications. As an example, it is possible to feed the electrical energy so produced into the national grid. In this regard, solar cells play extremely a major role while producing clean green energy to the future.

The current practice of the country of importing devices for capturing solar energy is not helping to meet the energy crisis in Sri Lanka as the cost involved with it is comparable or higher than that associated with fossil fuels. Therefore, the country cannot afford to install imported solar radiation capturing devices in large scale at the present high cost.

Owing to the high manufacturing cost and the limitation in further improvements of efficiency associated with the mostly used single and polycrystalline silicon solar cells, the scientists and engineers in the solar cell industry over the world are now concentrating their efforts for improving the efficiency and reducing the cost of production of the second generation of solar cells; “the thin film polycrystalline solar cells”. Among the three recognized thin film solar cells: Copper Indium Selenide (CIS), Copper Indium Gallium Selinide (CIGS) and Cadmium Sulfide/Cadmium Telluride (CdS/CdTe), the latter has received the highest attention as CdTe is the strongest absorber material of the solar radiation falling on earth.

Recently, the attention of research groups fabricating solar cells are focusing more on CdS/CdTe thin film polycrystalline solar cells & graded band gap solar cells and the technique of electrodeposition in fabrication of solar cells as it is simple, inexpensive and easily scalable. Nevertheless, performances of the solar cells need to be further improved and the cost of the production has to be further lowered and the procedure of deposition need to be made further simple in order for a country like Sri Lanka to be able to afford it. Therefore, it is worthwhile on investing for researches focusing on developing solar energy materials.

Objectives

Sensors and materials

To develop nanomaterials (ZnS, ZnO, CdS and CdTe) via electrodeposition and/or precipitate method & spin coating for gas (O2, NO2, NH3, CH4 and LP) sensing

Electrochemical power devices

• To develop gel polymer electrolytes based on several polymer host materials (polyethylene oxide (PEO), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN) polyvinylpyridine (PVP), prolypropyleglycol-methylmethacrylate (PPG-PMMA) etc ) as either cationic conductors or anionic conductors using appropriate ionic salts. 
• To check the possibilities of using newly developed electrolyte materials in rechargeable lithium/Magnesium batteries, dye sensitized solar cells, supercapacitors and electrochromic display devices. 

Solar energy materials

• To develop semiconductor materials (ZnS, ZnO, CdS and CdTe) for thin film solar cells via electrodeposition
• To fabricate CdS/CdTe and graded band gap thin film solar cells using electrodeposited ZnS, ZnO, CdS and CdTe thin films