A CuIn_1−xGa_xSe₂ (CIGS) photocathode having a specific composition exhibited remarkable promotion of hydrogen evolution from water, with a half-cell solar-to-hydrogen conversion efficiency of 12.5%. CIGS thin films with various compositions (defined by x = Ga/(In + Ga)) were prepared via a three-stage method employing a vacuum evaporation system. The photocurrent from CIGS photocathode surfaces modified with CdS and Pt (Pt/CdS/CIGS) significantly increased along with x as a result of a reduction in the conduction band offset at the CIGS/CdS interface. Using an optimized aqueous electrolyte resulted in enhanced photocurrents of 28 and 18 mA cm⁻² at 0 and 0.6 V_RHE, respectively, under simulated AM1.5G sunlight. A tandem-type PEC cell containing the newly developed CIGS photocathode and a BiVO₄ semi-transparent photoanode demonstrated stoichiometric hydrogen and oxygen evolution with a solar-to-hydrogen conversion efficiency of 3.7% without the application of an external bias voltage.

中文翻译：

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高效CuIn _0.5 Ga _0.5 Se ₂基光电阴极的开发及其在整体太阳能驱动水分解中的应用†

具有特定组成的CuIn _{1- x} Ga _x Se ₂（CIGS）光电阴极显着促进了氢从水中放出，半电池的太阳能转化为氢的效率为12.5％。通过采用真空蒸发系统的三步法制备具有各种组成（由x = Ga /（In + Ga）定义）的CIGS薄膜。由于CIGS / CdS界面处的导带偏移减小，来自用CdS和Pt修饰的CIGS光电阴极表面的光电流（Pt / CdS / CIGS）随x显着增加。使用优化的水性电解质可提高28和18 mA cm ^-2的光电流在模拟的AM1.5G阳光下分别处于0和0.6 V _RHE的条件下。包含新开发的CIGS光电阴极和BiVO ₄半透明光电阳极的串联式PEC电池在不施加外部偏压的情况下，化学计量的氢气和氧气逸出率达到了3.7％的太阳能转化效率。