Plasmonic p-n Junction for Infrared Light to Chemical Energy Conversion.

Infrared (IR) light represents an untapped energy source accounting for almost half of all solar energy and conversion of IR to chemical energy is a major challenge in usage of solar energy. Thus, there is a need to develop systems to convert IR light to fuel and make full use of this plentiful resource. Herein, we report photocatalytic H2 evolution driven by near- to shortwave-IR light (up to 2500 nm) irradiation, based on novel CdS/Cu7 S4 heterostructured nanocrystals. The apparent quantum yield reached 3.8% at 1100 nm, which exceeds the highest efficiencies achieved by IR light energy conversion systems reported to date. Spectroscopic results revealed that plasmon-induced hot-electron injection at p-n heterojunctions realizes exceptionally long-lived charge separation (> 273 μs), which results in efficient IR light to hydrogen conversion. These results pave the way for exploration of undeveloped low-energy light for solar fuel generation.