Generation of long-lived charges in organic semiconductor heterojunction nanoparticles for efficient photocatalytic hydrogen evolution
Generation of long-lived charges in organic semiconductor heterojunction nanoparticles for efficient photocatalytic hydrogen evolution
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DOI：
10.1038/s41560-022-00990-2
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发表时间：
2022-03-14
期刊：
影响因子：
56.7
通讯作者：
McCulloch, Iain
中科院分区：
文献类型：
--
作者：
Kosco, Jan;Gonzalez-Carrero, Soranyel;McCulloch, Iain
有机半导体异质结光催化剂在合成太阳能燃料方面有着广阔的应用前景，但要提高其性能还需要对其物理机制有更深入的了解。在这里，作者表明，这种材料本身可以产生非常长寿命的活性电荷，使它们能够有效地驱动析氢。用于生产太阳能燃料的有机半导体光催化剂是有吸引力的，因为它们可以通过合成调整来吸收可见光，同时保持合适的能级来驱动一系列过程。然而，需要更好地理解决定有机半导体异质结纳米颗粒功能的物理学，以优化性能。在这里，我们证明了这种材料可以内在地产生非常长寿命的活性电荷，使它们能够有效地驱动牺牲氢的析出。我们优化的异质结光催化剂包括与Y 6或PCBM电子受体匹配的共轭聚合物PM 6，并在400至900 nm和400至700 nm分别实现1.0%至5.0%和8.7%至2.6%的外量子效率。采用瞬态和operando光谱，我们发现，在这些纳米粒子的异质结结构大大提高了长寿命的电荷（毫秒至秒的时间尺度）的产生，即使在没有电子/空穴清除剂或Pt。这种长寿命的反应性电荷在水裂解Z-方案和驱动动力学缓慢和技术上理想的氧化中打开了潜在的应用。
Organic semiconductor heterojunction photocatalysts are promising for synthesis of solar fuels yet a deeper understanding of their underlying photophysics is needed to improve performance. Here, the authors show that such materials can intrinsically generate remarkably long-lived reactive charges, enabling them to efficiently drive hydrogen evolution.Organic semiconductor photocatalysts for the production of solar fuels are attractive as they can be synthetically tuned to absorb visible light while simultaneously retaining suitable energy levels to drive a range of processes. However, a greater understanding of the photophysics that determines the function of organic semiconductor heterojunction nanoparticles is needed to optimize performance. Here, we show that such materials can intrinsically generate remarkably long-lived reactive charges, enabling them to efficiently drive sacrificial hydrogen evolution. Our optimized hetereojunction photocatalysts comprise the conjugated polymer PM6 matched with Y6 or PCBM electron acceptors, and achieve external quantum efficiencies of 1.0% to 5.0% at 400 to 900 nm and 8.7% to 2.6% at 400 to 700 nm, respectively. Employing transient and operando spectroscopies, we find that the heterojunction structure in these nanoparticles greatly enhances the generation of long-lived charges (millisecond to second timescale) even in the absence of electron/hole scavengers or Pt. Such long-lived reactive charges open potential applications in water-splitting Z-schemes and in driving kinetically slow and technologically desirable oxidations.