As a result of a two-year joint project, materials researchers at Tallinn University of Technology in Estonia have improved the efficiency of next generation solar cells by partial substitution of copper with silver in absorber material. They published the results in the Journal of Materials Chemistry A.
The TalTech researchers are developing cells using an unusual compound semiconductor material called kesterite, a non-toxic competitor to perovskite with the formula Cu2ZnSn(Se,S)4,
To produce kesterites, TalTech researchers use a monograin powder technology, which they say is unique. "The monograin powder technology we are developing differs from other similar solar cell manufacturing technologies used in the world in terms of its method. Compared to vacuum evaporation or sputtering technologies, which are widely used to produce thin-film structures, the monograin powder technology is less expensive," explains Marit Kauk-Kuusik (pictured above), senior researcher at TalTech Laboratory of Photovoltaic Materials.
Powder growth involves heating the chemical components in a chamber furnace at 750degC for four days. Afterwards, the mass obtained is washed and sieved. The synthesised microcrystalline powder, monograin powder, is then used for the production of solar cells. The powder technology differs from other production methods in particular due to its low cost, since it does not require any expensive high vacuum equipment.