Effect of ultrasound treatment on CuInSe2 solar cells

Thin CuInSe2 films on glass substrate and solar cells were processed using the ultrasound treatment technique (UST). The SIMS measurements on the films showed a strong reduction of the Na-signal after the UST, which is most likely caused by ultrasonically induced chemical reaction of the mobile sodium ions. The change of the solar cell efficiency due to the UST depends on the initial efficiency. For the cells with efficiencies below 10% relative improvements of up to 50% are observed. On the contrary, the cells with higher efficiencies remain stable after the UST. In addition, parameters of CuInSe2 cells affected by the UST show the relaxation.