We synthesized CuAlS₂/ZnS quantum dots (QDs) composed of biocompatible, earth-abundant elements that can reduce salts of carbon dioxide under visible light. The use of an asymmetric morphology at a type-II CuAlS₂/ZnS heterointerface balances multiple requirements of a photoredox agent by providing a low optical bandgap (∼1.5 eV), a large optical cross section (>10^–16 cm² above 1.8 eV), spatial proximity of both semiconductor components to the surface, as well as photochemical stability. CuAlS₂/ZnS QDs thus have an unprecedented photochemical activity in terms of reducing carbon dioxide in the form of aqueous sodium bicarbonate under visible light, without the need for a cocatalyst, promoter, or sacrificial reagent while maintaining large turnover numbers in excess of 7 × 10⁴ per QD. Devices based on these QDs exhibit energy conversion efficiencies as high as 20.2 ± 0.2%. These observations are rationalized through our spectroscopic studies that show short 550 fs electron dwell times in these structures. The high energy efficiency and the environmentally friendly composition of these materials suggest a future role in solar light harvesting.

中文翻译：

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利用可见光量子点有效地从碳酸氢根离子光合作用

我们合成了CuAlS ₂ / ZnS量子点（QDs），该量子点由生物相容的，富含地球的元素组成，可以在可见光下还原二氧化碳的盐。在II型CuAlS ₂ / ZnS异质界面上使用非对称形态，通过提供低的光学带隙（〜1.5 eV），大的光学截面（> 1.8 eV大于10 ^–16 cm ²），可以平衡光氧化还原剂的多种要求。），两个半导体组件与表面的空间接近性以及光化学稳定性。铜铝₂因此/ ZnS QD在减少可见光下以碳酸氢钠水溶液形式减少二氧化碳方面具有空前的光化学活性，而无需助催化剂，促进剂或牺牲试剂，同时保持超过7×10 ^4的大周转率每个QD。基于这些QD的设备显示出高达20.2±0.2％的能量转换效率。通过我们的光谱研究合理化了这些观察结果，表明这些结构中的电子停留时间短至550 fs。这些材料的高能效和对环境友好的成分表明其在太阳光收集中的未来作用。