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.

用于生产太阳能燃料的有机半导体光催化剂很有吸引力，因为它们可以被合成调谐以吸收可见光，同时保持合适的能量水平来驱动一系列过程。然而，需要对决定有机半导体异质结纳米粒子功能的光物理学有更深入的了解，以优化性能。在这里，我们展示了这种材料本质上可以产生非常长寿命的反应电荷，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含与 Y6 或 PCBM 电子受体匹配的共轭聚合物 PM6，在 400 至 900 nm 和 400 至 700 nm 处分别实现 1.0% 至 5.0% 和 8.7% 至 2.6% 的外部量子效率。使用瞬态和操作光谱，我们发现即使在没有电子/空穴清除剂或 Pt 的情况下，这些纳米颗粒中的异质结结构也极大地增强了长寿命电荷（毫秒到秒时间尺度）的产生。这种长寿命的活性电荷在水分解 Z 方案和驱动动力学缓慢和技术上理想的氧化方面具有潜在的应用前景。