Enhancing Photocatalytic Hydrogen Evolution by Improving the Morphology of Organic Semiconductor Nanoparticles with TCB Additive

Organic semiconductor nanoparticles (NPs) are promising organic photocatalysts for water splitting. However, effective organic semiconductor NPs require efficient charge dissociation and transport at the heterojunction interface. Common core-shell structured NPs exhibit low hydrogen evolution rates (HERs) due to limited charge dissociation efficiency. Here, this challenge is addressed by introducing 1,3,5-trichlorobenzene (TCB) additive into organic semiconductor NPs to improve their heterojunction morphology. As a result, PM6:Y6 NPs with TCB have a more intimately blended morphology, which enhances charge dissociation and transport. These NPs achieve a HER of 16,490 µmol g^-1 h^-1, which is more than twice that of NPs without TCB. Further optimization of the NPs concentration led to a remarkable HER of 58,400 µmol g^-1 h^-1. Moreover, the PM6:Y6 NPs with TCB exhibit better operational stability due to their enhanced morphological stability. This study demonstrates the effectiveness of the additive strategy in improving the heterojunction morphology of organic semiconductor NPs to overcome key limitations of their photocatalytic hydrogen evolution efficiency and provides valuable insights for the development of high-performance organic photocatalysts.