Studies on Chemical Bath Deposited Semiconducting Copper Selenide and Iron Sulfide Thin Films Useful For Photovoltaic Applications

Chemical bath deposition (CBD)is one of the simplest, very convient and probably the cheapest method for thin film preparation. Photovoltaic is the cleanest and the most efficient mode of conversion of energy to electrical power. Silicon is the most popular material in this field. The present study on chemical bath deposited semiconducting copper selenide and iron sulfide thin films useful for photovoltaic applications. Semiconducting thin films prepared by chemical deposition find applications as photo detectors, solar control coatings and solar cells. Copper selenide is a p-type semiconductor that finds application in photovolitics. Several heterojunction systems such as Cu2-xSe/ZnSe (for injection electro luminescence), Cu2Se/AgInSe2 and Cu2Se/Si (for photodiodes), Cu2-xSe/CdS, Cu2-xSe/CdSe, CuxSe/InP and Cu2-xSe/Si for solar cells are reported. A maximum efficiency of 8.3% was achieved for the Cu2-xSe/Si cell, various preparation techniques are used for copper selenide like vacuum evaporation, direct reaction, electrodeposition and CBD. Instability of the as-prepared films was investigation and is accounted as mainly due to deviation from stoichiometry and the formation of iron oxide impurity. A sulphur annealing chamber was designed and fabricated for this work. These samples wee also analysed using optical absorption technique, XPS (X-ray Photoelectron Spectroscopy) and XRD.(X-Ray Diffraction).The pyrite films obtained by CBD technique showed amorphous nature and the electrical studies carried out showed the films to be of high resistive nature. Future work possible in the material of iron pyrite includes sulphur annealing of the non-stochiometric iron pyrite CBD thin films in the absence of atmospheric oxygen

Haematological responses of green mussel Perna viridis (Linnaeus) to heavy metals copper and mercury

Department of Marine Biology, Microbiology and Biochemistry, Cochin University of Science and Technology

Toxicological effects of Copper and Mercury on the fish Macrones gulio (Hamilton-Buchanan)

Asha M. R This thesis Entitled Toxicological effects of copper and mercury on the fish macerones gulio (hamiloton – buchanan).Chapter 1. In this chapter, a broad outline of heavy metal uptake, requirement of a suitable bio — monitoring organism, criteria for a standard test fish, and suitability of Macrones gulig for the toxicological study are given. Chapter 2. This chapter deals with the lethal toxicity bioassays to find the 96 hr LC 50 of copper and mercury for the fish Macrones gglig. The experimental results indicated that of the two metals tested, copper was more toxic than mercury.Chapter 3. The effect of copper and mercury on the haemoglobin, haematocrit, erythrocyte count, MCV, MCH and MCHC was studied.Chapter 4. The glycogen and protein contents of liver and muscle after exposure to copper and mercury were studied. There was a significant decrease of glycogen in the liver and muscle of metal treated fishes.Chapter 5. The histopathological changes of the tissues like liver, kidney and gill after exposure to copper and mercury were studied.

Studies on the effect of toxic heavy metal mercury on the physiology and biochemistry of an estuarine crab Scylla serrata (Forskal)

This thesis Entitled studies on the effect of toxic heavy metal mercury on the physiology and biochemistry of an estuarine crab scylla serrata (Forskal). Evaluate the toxicity of three sub lethal concentrations of mercury, viz., 0.009 mg/l, 0.02 mg/1, and 0.04 mg/l on the mud crab, Scylla serrata through bioaccumulation, and depuration studies. To characterize the biochemical responses to the sub-lethal stress of mercury in chelate muscles, abdominal muscles, hepatopancreas and gills. To study the activity pattern of acid and alkaline phosphatases in mercury-exposed crabs. To evaluate the induced changes in these tissues through histopathological studies,The Cochin backwaters is one of the most productive and biologically active backwater systems, and is the habitat of varieties of fishes, mollusks, and crustaceans, though this water body also receives tons of effluents from factories located on the banks of the river, Periyar.To study the activity levels of acid and alkaline phosphatases in crabs, at three time periods, exposed to three sub lethal concentration of mercury,