The Study On Electrodeposition Of Silicon In Nonaqueous Solvent

Photovoltaic has distinctive advantages .First, it can be used widely and perpetually, second, when used it is safer than nuclear energy and causes no pollution. So since 1960s, people have paid much attention to its use and development. Having been developed for more than 50 years, solar cell is used not only in space flight but also in civilian use. It is no doubt that photovoltaic will be the most important energy in the future. Unfortunately, due to high cost, silicon base solar cell can hardly compete with conventional source of energy, which restricts large-scale application of silicon base solar cell. Therefore reducing the cost of silicon base solar cell becomes collaborative aim of all researchers and companies.For nonaqueous solvent has distinctive properties, lots of reactions which can't happen in aqueous can carry out in nonaqueous solvent, researchers wish to electrodeposit semiconductor in nonaqueous solvent and to fabricate P-type or N-type Si film directly. If silicon can be prepared in nonaqueous solvent in room temperature,it is very possible to produce large-scale silicon base solar cell continuously and to reduce cost of photovoltaic substantially, then the cost of silicon base solar cell can reduce dramatically. Now some developed countries have studied in this field already, unfortunately, there is no study in this field in China.In this paper, we consider electrodeposit of silicon in nonaqueous solvent. First we choose silicon tetrachloride as silicon source, propene carbonate as solvent, tetrabutylammonium chloride as supporting electrolyte and nickel as working electrode for our experiments. When electric potential is around -2.69827V, we can obtain silicon in electrodeposit layer. When the time of electrodeposit is 0.5 hours, the amount of silicon is only little. As the time of electrodeposit extends from 1 hour to 4 hours, the amount of silicon increases from 1.30% to 6.02%.Raman spectra indicates that silicon obtained by electrodeposit in this system is amorphous silicon and can be used to produce solar cell. GDS spetra illustrates silicon concentrates on the surface of deposit, which is beneficial to save silicon and to cut down the cost of thin-film solar cells.According to slight oxidation of nickel in experiment, we choose alloy of titanium, nickel and niobium which has outstanding corrosion resistance as working electrode for the first time. Cyclic voltammograms shows that when electric potential is around -2.3969V, we can obtain silicon in electrodeposit layer. When alloy of titanium, nickel and niobium used as working electrode, amount of silicon is more than nickel used as working electrode. Meanwhile corrosion never happens to alloy of titanium, nickel and niobium in our experiment .Both above prove that in this system, alloy of titanium, nickel and niobium is more suitable to used as working electrode. The amount of silicon increases obviously as the time of electrodeposit prolongs. Silicon concentrates on the surface and reduces rapidly as distance from surface increases.This distribution characteristic satisfies requirement of low cost of thin-film solar cells.Finally, we choose silicon tetrachloride as silicon source, propene carbonate as solvent, tetrabutylammonium chloride as supporting electrolyte and SUP13Cr stainless steel as working electrode for the first time. Cyclic voltammograms shows that when electric potential is around -3.12774V, silicon can be reduced. As the time of electrodeposit extends from 1 hour to 4 hours,the amount of silicon increases from 3.33% to 9.29%.