11.5% efficient Cu₂ZnSn(S,Se)₄ solar cell fabricated from DMF molecular solution

Abstract

The weak Sn–O coordination bonds in Sn(DMF)2Cl4 result in the formation of a kesterite phased (Cu2ZnSnS4) precursor film and thus fabrication of a highly efficient Cu2ZnSn(S,Se)4 absorber from DMF solution.

DMF‐Based Large‐Grain Spanning Cu2ZnSn(Sx,Se1‐x)4 Device with a PCE of 11.76%

“…The weak diffraction peaks at 32.2° are attributed to Mo(Se,S) 2 . [ 19 ] No additional peaks from impurity are observed. The full width at half maximum values of (112) peak of the CZTSSe decreases from 0.23° to 0.07° with the increase in temperature, which indicates that the crystallinity of the absorbers is improved after pre‐annealing (Figure S3, Supporting Information).…”

“…The peak at 326 cm –1 is the characteristic peak of CZTS. [ 19 ] There are no additional secondary phases. Meanwhile, CZTSSe Raman peaks become sharp as the temperature increases from 350 to 450 ℃, indicating the increased crystallinity caused by the pre‐annealing process, which is consistent with the XRD results.…”

“…Niu et al. [ 19 ] used Cu 1+ and Sn 4+ as reaction materials to effectively avoid the production of the secondary phases. However, Cu 2+ and Sn 2+ were employed to ensure the high purity of CZTSSe in this work.…”

“…However, Cu 2+ and Sn 2+ were employed to ensure the high purity of CZTSSe in this work. Cu(oAC) 2 ·H 2 O, ZnCl 2 , and TU form two kinds of complexes (see Equation ), [ 19 ] SnCl 2 ·2H 2 O and DMF from the third kind of complex (see Equation ). [ 19 ] Redox reaction occurs among the above three kinds of complexes.…”

“…Cu(oAC) 2 ·H 2 O, ZnCl 2 , and TU form two kinds of complexes (see Equation ), [ 19 ] SnCl 2 ·2H 2 O and DMF from the third kind of complex (see Equation ). [ 19 ] Redox reaction occurs among the above three kinds of complexes. Cu 2+ is reduced to Cu 1+ and Sn 2+ is oxidized to Sn 4+ , leading to the CZTS production (see Equation ).…”