Electrophoretic deposition of colloidal nanoparticles for synthesis of chalcopyrite thin films

A non-vacuum technique for fabrication of chalcopyrite thin films has been developed based on electrophoretic deposition of colloidal nanoparticles. Colloidal suspensions of Cu-In composite nanoparticles were produced with high power pulsed laser ablation in liquid solvents. The nanoparticles inherit the composition (i.e., Cu-In ratio) from the Cu-In alloy target during laser ablation. CuInSe₂ absorber layers were formed by electrophoretic deposition of the nanoparticles onto conductive substrate, followed by selenization in selenium vapor under atmospheric pressure. Solar cell device made using the fabricated absorber layer demonstrated a total-area cell efficiency of 2.5%-3.0%. The results open up a new route of non-vacuum fabrication of thin film chalcopyrite solar cells on flexible substrates with minimized chemical contamination, easy compositional control, and high raw material utilization.