Photovoltaic cell technology has received a boost with the announcement that expensive and toxic components can be replaced with ingredient used to coagulate soya milk into tofu and found in bath salts. The cadmium telluride cells are much thinner and have a lower cost per watt than silicon but require the addition of another compound, usually cadmium chloride, a soluble salt, to improve efficiency to make it commercially feasible.
Jonathan Major, who lead the study at the University of Liverpool (UK), said that after the experiments they have replaced cadmium chloride for much cheaper and non-toxic compound, magnesium chloride, which is extracted from sea water. The research results are published in the journal of Nature and indicate that the efficiency of converting solar energy into electricity is about 13 % if any of the two compounds is used. However, it remains to prove the stability of these new solar cells to continue toward commercial production.
While cadmium telluride, the basis of these thin-film photovoltaic cells, is a stable compound with little risk, the use of cadmium chloride during the manufacturing process is safety hazard for workers and the environment.
“If we want solar PV compete with they the energy from fossil fuels, we should lower cost per watt generated and this is a step toward that goal,” said Major.
Experiments have shown that, magnesium was present in the cells made with the traditional compound. It came from the glass substrate and did not affect its operation. However, other chlorides that have been tested do affect behavior by introducing electrically active impurities.
The work was presented at the Euroscience open forum (ESOF) 2014 conference brings together some 4,000 participants and is the largest interdisciplinary meeting held in Europe.