Fabrication of Cu(In,Ga)Se2 Films by a Combinationof Mechanochemical Synthesis, Wet Bead Milling, anda Screen-Printing/Sintering Process

摘要

We prepared fine Cu(In,Ga)Se2 (CIGS) powder suitable for screen printing using a mechanochemical synthesis and wet bead milling. Particulate precursors were deposited in a layer by a screen-printing technique, and the porous precursor layer was sintered into a dense polycrystalline film by atmospheric-pressure firing in an N2 gas atmosphere. The microstructure of CIGS powder and fired CIGS film were observed in an SEM. The wet bead milling was effective for the reduction and homogenization of the average grain size of CIGS powder. The CIGS grains in the film were well sintered and the size of CIGS grains was as large as about 2 μm. The CIGS solar cell showed an efficiency of 3.1 %, with V_(oc) of 0.279 V, J_(sc) of 28.8 mA/cm~2 and FF of 0.386.