CZTSSe Preparation method for CZTSSe-based film and manufacturing method for film solar cell by using the preparation method

摘要

Provided are a method for manufacturing a CZTSSe-based thin film and a method for manufacturing a thin film solar cell using the same. The method for manufacturing a CZTSSe-based thin film of the present invention comprises the steps of: forming a precursor thin film including a metal; pre-annealing a sulfur source and a selenium source while supplying the same to the precursor thin film; and performing selenization heat-treatment for the pre-annealed precursor thin film. In the step of pre-annealing of the precursor thin film, a metal sulfoselenide compound layer is formed in the precursor thin film. In the selenization heat-treatment step, a band gap gradient is formed in the precursor thin film by using the metal sulfoselenide compound layer as a sulfur supply source. According to the present invention, the band gap gradient is easily formed by forming the metal sulfoselenide compound layer in the thin film through the pre-annealing step at low temperatures and using the same as a sulfur source in a main heat-treatment step, and an additional process is not required to easily perform a process. In addition, the formed band gap gradient is continuously maintained at high temperatures to increase an open voltage and electron mobility and to reduce recombination of electron-hole, thereby manufacturing a thin film solar cell with improved efficiency.