High mobility organic semiconductor for constructing high efficiency carbon nitride heterojunction photocatalysts

Graphitic carbon nitride (CN) has attracted worldwide attention due to its low-cost, environmental friendliness and tunable structures. However, the CN photocatalyst still suffers from low charge separation efficiency issues. It is known that mobility is one of the most important factors dominating the charge separation and transport. This work reports a new strategy to address the low charge separation issue by coupling a high-mobility organic semiconductor and CN. Copper phthalocyanine (CuPc), a classical small molecule organic semiconductor which possesses high mobility, outstanding stability and strong visible-light absorption, was selected to construct CN/CuPc heterojunctions. The CN/CuPc heterojunctions showed a high hydrogen evolution (PHE) rate of 9.0 mmol g−1 h−1 and apparent quantum yield (AQY) of 3.99% (420 nm) and 1.31% (600 nm). This work demonstrates the application prospects of high-mobility organic semiconductors in heterojunction photocatalysis.