Exciton-Mediated Energy Transfer in Heterojunction Enables Infrared Light Photocatalysis

Although a few semiconductors can directly absorb infrared light, their intrinsic properties like improper band-edge position and strong electron-hole interaction restrict further photocatalytic applications. Herein, we propose an exciton-mediated energy transfer strategy for realizing efficient infrared light response in heterostructures. Using black phosphorous/polymeric carbon nitride (BP/CN) heterojunction, CN could be indirectly excited by infrared light with the aid of nonradiatively exciton-based energy transfer from BP. At the same time, excitons are dissociated into free charge carriers at the interface of BP/CN heterojunction, followed by hole injection to BP and electron retainment in CN. As a result of these unique photoexcitation processes, BP/CN heterojunction exhibits promoted conversion rate and selectivity in amine-amine oxidative coupling reaction even under infrared light irradiation. This study opens a new way for the design of efficient infrared light activating photocatalysts.

Automated summary

This study proposes an exciton-mediated energy transfer strategy in heterostructures to achieve efficient infrared light response in semiconductors. By utilizing a black phosphorous/polymeric carbon nitride (BP/CN) heterojunction, improved conversion rate and selectivity in amine-amine oxidative coupling reaction under infrared light irradiation were observed. This research opens up a new approach for designing efficient photocatalysts activated by infrared light.