Triplet energy transfer between inorganic nanocrystals and organic molecules

Merging the light- harvesting and emitting capability of inorganic materials with the versatile excited-state properties of organic molecules leveraging triplet energy transfer (TET) has recently become an important design strategy for light-driven applications ranging from energy conversion, biomedicine, to photoredox catalysis, and understanding the rules that govern such phenomena is essential. Recent years have witnessed some breakthroughs of TET as well as significant advances for regulating this photochemical process, but it still needs more integrated research at the center. In particular, efficient TET between semiconductor nanocrystals (or quantum dots) and organic molecules, which combines nanoscale size effect of the former and molecular versatility of the latter, has been demonstrated as a promising enabler for breaking the Shockley-Queisser limit in solar energy conversion, controlling photon emission, and driving photochemical reactions in the years to come. Here we review the fundamentals of TET mechanism and some of its emerging applications, with special focus on recent progress towards the understanding and application of TET in nanocrystal-molecule hybrids and highlight some challenges for the field. Work is currently aimed at providing insights in controlling TET dynamics with a view to making the process as efficient as possible according to expected designs.