Understanding the origin of disorder in kesterite-type chalcogenides A₂ZnBQ₄ (A = Cu, Ag; B = Sn, Ge; Q = S, Se): the influence of inter-layer interactions

Abstract

Neutron diffraction coupled with density functional theory provides new insights into the structural features of quaternary chaclogenides.

Defect Control for 12.5% Efficiency Cu2ZnSnSe4 Kesterite Thin‐Film Solar Cells by Engineering of Local Chemical Environment

“…[3,13,20] Li and Na have been proven to reduce the nonradiative recombination centers as well as to improve the p-type doping density. [21,22] Isovalent cation substitution, such as substituting Ag for Cu, [23][24][25] Cd for Zn, [26][27][28] and Ge for Sn, [16] has demonstrated pronounced improvements in electronic properties and device performance compared to reference solar cells. Despite these efforts, the record efficiency for kesterite solar cells is still held by devices with nominally no doping nor cation substitution (but may, however, unintentionally incorporating Na from the glass substrates).…”

The impact of a magnetic ion on the thermoelectric properties of copper-rich quaternary selenides

“…However, as noted above, discrimination between these two structure types is not possible on the basis of powder x-ray diffraction alone. On the basis of our previous work utilising a combination of powder neutron diffraction and DFT [17], we hereafter describe materials of general formula Cu 2+x ZnGe 1−x Se 4 in a kesterite-type structure, whereas following the work of Schafer and Nitsche [20] phases of the form Cu 2+x FeGe 1−x Se 4 are described in the stannite-type structure. Rietveld refinements using powder x-ray diffraction data for as-prepared Cu 2+x ZnGe 1−x Se 4 (0 ⩽ x ⩽ 0.15) were therefore initiated in the space group I 4, using our previous results [17] from powder neutron diffraction for the initial structural model.…”

“…On the basis of our previous work utilising a combination of powder neutron diffraction and DFT [17], we hereafter describe materials of general formula Cu 2+x ZnGe 1−x Se 4 in a kesterite-type structure, whereas following the work of Schafer and Nitsche [20] phases of the form Cu 2+x FeGe 1−x Se 4 are described in the stannite-type structure. Rietveld refinements using powder x-ray diffraction data for as-prepared Cu 2+x ZnGe 1−x Se 4 (0 ⩽ x ⩽ 0.15) were therefore initiated in the space group I 4, using our previous results [17] from powder neutron diffraction for the initial structural model. Structural refinement of materials in the series Cu 2+x FeGe 1−x Se 4 (0 ⩽ x ⩽ 0.15) was initiated in the space group I 42m, using data for Cu 2 FeGeSe 4 [20] for the initial structural model.…”

“…The potential for cation disorder adds further complexity. A recent investigation [17] of A 2 ZnBQ 4 (A = Cu, Ag; B = Sn, Ge; Q = S, Se) using a combination of neutron diffraction and Density-Functional Theory (DFT) simulations identifies kesterite as the structure adopted, albeit with partial cation ordering in the copper-containing phases. Introduction of an open-shell transition-metal ion may have an impact on the relative energies of the two alternatives, and the parent material, Cu 2 FeGeSe 4 , of the series investigated in this work, has been described in both the stannite and kesterite forms [18,19].…”

Research Progress of Metal(I) Substitution in Cu2ZnSn(S,Se)4 Thin Film Solar Cells

“…因此, Ag 替位 Cu 掺入晶格后会引起晶 格体积膨胀, 相应的晶格参数也会发生改变. Powell 等 利用 DFT 计算了 Kesterite 相 A 2 ZnBQ 4 (A＝Cu, Ag; B＝ Ge, Sn; Q＝S, Se)的晶胞参数 [63] , Ag [44] . Maeda 等 [69] 制备了(Cu 1-x Ag x ) 2 ZnSnS(Se) 4 粉体, 研究了带隙随 替位量 x 变化规律, 见图 5.…”