In Situ Analysis of the Zn(S,O) Buffer Layer Preparation for Chalcopyrite Solar Cells by Zn L-edge X-Ray Absorption Spectroscopy

摘要

The final treatment for ZnACHTUNGTRENUNG(S,O) after deposition on CuInS2 is post-annealing at 2008C in air and 5 min of light soaking, which enhances the efficiency from about 8 to 10%. This significant enhancement upon post-annealing and light soaking is not yet fully understood.[7, 9, 10] The lack of understanding of these processes impedes further systematic improvements of the efficiency of chalcopyrite solar cells. Here we show that bridging the gap between high-vacuum soft X-ray spectroscopes and the real system under ambient conditions[21, 22] allows us to extend the applicability of soft X-ray absorption spectroscopy (XAS) to probe chemical reactions in situ during the CBD and annealing processes by probing the L-edge of Zn species in solution under ambient conditions. Furthermore, we show that as ligand-to-metal and metal-to-ligand charge transfer (LMCT and MLCT) increase, the quality of the resulting buffer layer also improves. Accordingly, reagents containing p-bonded complexes with strong LMCT and MLCT would be recommended for the CBD process.