Beyond-1000 nm low-energy sunlight-driven photocatalysis enabled by quantum dot-based photon upconversion

Solar energy harvesting and conversion are pivotal to sustainable chemistry and green chemistry, yet fundamental bottlenecks persist. A key unresolved challenge is chemical transformations driven by low-energy sunlight, especially beyond 1000 nm, which is limited by insufficient absorption and low photon energy. Here, we employ PbS quantum dots (QDs) as near-infrared-II (NIR-II) absorbers and precisely modulate the CdS shell to balance the triplet exciton transfer efficiency with the triplet lifetime of the surface ligands, thereby enhancing the overall sensitization performance of the hybrid photosensitizer. Coupled with rubrene as the annihilator, a record upconversion efficiency of 3.9% was achieved under 1064 nm excitation. Furthermore, the efficient upconversion material enables unprecedented beyond-1000 nm low-energy sunlight-driven large-volume photocatalysis, applicable to both free radical polymerization and atom transfer radical polymerization. This work establishes a foundation for advanced solar energy technologies with broad implications for photocatalysis and next-generation photovoltaics.