Enhanced photocatalytic hydrogen evolution by extending exciton lifetime via asymmetric organic semiconductor

To achieve high performance organic photovoltaic hydrogen-evolution (OPH), it is crucial to extend the exciton lifetime of organic photovoltaic catalysis. This is primarily because it increases the exciton diffusion length. In this work, a new asymmetric organic photovoltaic catalysis (BTP-eC9-B4F) has been developed, which achieves a longer exciton lifetime of 1.25 ns and a higher fluorescence quantum yield of 9.4 % compared to symmetric structures. This has been made possible by using asymmetric end groups. Experimental results demonstrate that the photocatalyst with a longer exciton lifetime exhibits a more efficient average hydrogen evolution rate of 121.57 mmol h−1 g−1 under AM 1.5G, 100 mW cm−2 for 5 h. Therefore, extending the lifetime of excitons has been shown to be an effective approach to achieve high efficiency OPH.