The bulk heterojunction (BHJ) concept, which has been successfully developed for organic semiconductor-based photovoltaic devices, offers a promising route to high-performance and inexpensive photocatalyst nanoparticles for solar hydrogen production. However, the suitability of organic semiconductors (OSs) towards robust and high efficiency photocatalytic water splitting remains an open question. Herein, efforts to understand the stability of OS-based BHJ photoelectrodes for both solar driven water reduction [1] and oxidation [2] are discussed. The integration of a BHJ photoanode and photocathode into a bias-free solar-driven water splitting device is also reported. Finally, the important aspects needed for translating these systems into nanoparticle photocatalysts are examined.

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References:
[1] L. Yao, N. Guijarro, F. Boudoire, Y. Liu, A. Rahmanudin, R. A. Wells, A. Sekar, H.-H. Cho, J.-H. Yum, F. Le Formal, K. Sivula, J. Am. Chem. Soc. 2020, 142, 7795.
[2] H.-H. Cho, L. Yao, J.-H. Yum, Y. Liu, F. Boudoire, R. A. Wells, N. Guijarro, A. Sekar, K. Sivula, Nat. Catal. 2021, 4, 431.