Method for preparing sol-gel solution for CIGS solar cell

A method for preparing a sol-gel solution for fabricating a copper/indium/gallium/selenium (CIGS) solar cell, the sol-gel solution being adapted for forming a GIGS light absorbing layer of the GIGS solar cell in accordance with a thin film deposition method, the method comprising:

• Step A:
• executing a first stage mixture preparation process for forming a metal compound mixture comprising Cu, In, Ga and Se, a diluting dispersant, a stabilizing adhesive, an anti-freezing coagulant, and a metallic reducing agent, respectively, and then entering step B;
• Step B:
• executing a second stage mixture preparation process for mixing the metal compound mixture of Cu, In, Ga, and Se, the diluting dispersant, the stabilizing adhesive, the anti-freezing coagulant, and the metallic reducing agent up to obtain a second stage mixture, and then entering step C;
• Step C:
• heating the second stage mixture to a first predetermined temperature, and then executing a first stirring operation for a first predetermined time, and then entering step D;
• Step D:
• cooling the second stage mixture down to a second predetermined temperature, and then executing a second stirring operation for a second predetermined time, and then entering step E;
• and
• Step E:
• cooling the second stage mixture to obtain the sol-gel solution.