A 19.5%‐efficient Cu(In,Ga)(S,Se)₂ (CIGSSe)‐based solar cell is obtained by replacing traditional CdS/ZnO buffer layers with Cd_0.75Zn_0.25S/Zn_0.79Mg_0.21O buffer layers for increasing short‐circuit current density because band‐gap energies of Cd_0.75Zn_0.25S and Zn_0.79Mg_0.21O are wider than those of CdS and ZnO, respectively. This yields the increase in external quantum efficiency in a short wavelength range of approximately 320 to 550 nm. Moreover, difference of conduction band minimum (E_C) between Zn_1 − xMg_xO:Al (transparent conductive oxide, TCO) layer and CIGSSe absorber is optimized by varying [Mg]/([Mg] + [Zn]), x. It is revealed that Zn_1 − xMg_xO:Al films with [Mg]/([Mg] + [Zn]) in a range of 0.10 to 0.12, enhancing E_g from 3.72 to 3.76 eV, are appropriate as TCO because of their enhanced mobility and decreased carrier density. Addition of 12% Mg into ZnO:Al to form Zn_0.88Mg_0.12O:Al as TCO layer effectively decreases surface carrier recombination and improves photovoltaic parameters, especially open‐circuit voltage and fill factor. This is the first experimental proof of the concept for optimizing E_C difference between TCO and absorber to minimize surface carrier recombination. Ultimately, conversion efficiency (η) of CIGSSe solar cell with alternative Cd_0.75Zn_0.25S/Zn_0.79Mg_0.21O/Zn_0.88Mg_0.12O:Al (TCO) layers is enhanced to 20.6%, owing to control of total E_C alignment, which is higher η up to 12.6% relative as compared with the solar cell with traditional CdS/ZnO/ZnO:Al layers.

中文翻译：

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铝掺杂的Zn1-xMgxO作为基于Cu（In，Ga）（S，Se）2的太阳能电池的透明导电氧化物，可最大程度地减少表面载流子复合

通过用Cd _0.75 Zn _0.25 S / Zn _0.79 Mg _0.21 O缓冲层替代传统的CdS / ZnO缓冲层以增加效率，可得到效率为19.5％的Cu（In，Ga）（S，Se）₂（CIGSSe）基太阳能电池Cd _0.75 Zn _0.25 S和Zn _0.79 Mg _0.21 O的带隙能分别比CdS和ZnO的带隙能宽。这样在大约320至550 nm的短波长范围内提高了外部量子效率。此外，Zn _{1 −  x} Mg _x之间的导带最小值（E _C）之差通过改变[Mg] /（[[Mg] + [Zn]），x优化O：Al（透明导电氧化物，TCO）层和CIGSSe吸收剂。结果表明，ZnO _{1-  x} Mg _x O：Al膜的[Mg] /（[[Mg] + [Zn]）在0.10至0.12的范围内，使E _g从3.72至3.76 eV增强，适合作为TCO，因为增强了迁移率并降低了载流子密度。在TCO层中向ZnO：Al中添加12％Mg以形成Zn _0.88 Mg _0.12 O：Al可有效减少表面载流子复合并改善光伏参数，特别是开路电压和填充系数。这是优化E _C概念的第一个实验证明。TCO和吸收剂之间的差异，以最大程度地减少表面载体的重组。最终，由于控制了总的E _C对准，具有替代Cd _0.75 Zn _0.25 S / Zn _0.79 Mg _0.21 O / Zn _0.88 Mg _0.12 O：Al（TCO）层的CIGSSe太阳能电池的转换效率（η）提高到20.6％。与具有传统CdS / ZnO / ZnO：Al层的太阳能电池相比，它的η高达12.6％。