Exploring Sb2Se3 as a photoelectrochemical (PEC) photocathode for water reduction has recently attracted much attention, mainly due to its excellent photophysical properties and perfect band structure matching with water reduction potential. Whereas significant achievements have been made in improving its photocurrent density, the PEC performance remains poor mostly due to the low onset potential or low fill factor. Here, we fabricated S doped Sb2Se3 nanowire arrays with a gradient S concentration (grad-S:Sb2Se3). Gradient S doping creating a cascade valence band structure in Sb2Se3 simultaneously enhances its onset potential and fill factor. Light-trapping effects in nanowire geometry improve the light harvesting efficiency. A further deposition of a thin TiO2 layer is utilized to passivate the detrimental surface defects and form a buried junction with grad-S:Sb2Se3. By employing the prepared grad-S:Sb2Se3 nanowire arrays as the photocathode for water reduction, we achieved a high onset potential of 0.42 V vs RHE, a fill factor of 34%, and a record high half-cell solar-to-hydrogen conversion efficiency of 2% from Sb2Se3-based photocathodes.

中文翻译：

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在 Sb2Se3 纳米线阵列中梯度掺杂硫作为光电化学光电阴极，半电池太阳能到氢的转换效率为 2%

探索 Sb2Se3 作为用于水还原的光电化学 (PEC) 光电阴极最近引起了很多关注，这主要是由于其优异的光物理性质和与水还原电位匹配的完美能带结构。尽管在提高其光电流密度方面取得了重大成就，但 PEC 性能仍然很差，主要是由于低起始电位或低填充因子。在这里，我们制造了具有梯度 S 浓度（grad-S:Sb2Se3）的 S 掺杂 Sb2Se3 纳米线阵列。梯度 S 掺杂在 Sb2Se3 中创建级联价带结构同时增强其起始电位和填充因子。纳米线几何中的光捕获效应提高了光收集效率。薄 TiO2 层的进一步沉积用于钝化有害的表面缺陷并与 grad-S:Sb2Se3 形成掩埋结。通过使用制备的 grad-S:Sb2Se3 纳米线阵列作为光阴极进行水还原，我们实现了 0.42 V vs RHE 的高起始电位，34% 的填充因子，以及创纪录的高半电池太阳能到氢气的转化率Sb2Se3 基光电阴极的效率为 2%。