Recently, the iChEM researchers Prof. Cheng Wang , Prof. Wenbin Lin and their groups from Xiamen University made significant progress in the research about the energy transport of singlet exciton. The result was published in the journal J. Am. Chem. Soc as “Förster Energy Transport in Metal-Organic Frameworks Is Beyond Step-by-Step Hopping” and was selected as ACS Editors’ Choice.

The dynamics of exciton migration in the frameworks was monitored by employing coumarin dye molecules in the MOF cavity as an emissive observer and acceptor for energy transfer. Metal-organic frameworks (MOFs) with light harvesting building blocks mimicked the antenna array for light-harvesting in natural photosynthetic systems, and coumarin dyes mimicked the reaction centers that accept the excitons. A step-by-step exciton random hopping model made of the elementary steps of energy transfer between only the nearest neighbors is usually used to describe singlet exciton migration in the light harvesting networks. In this work, by performing simple and effective fluorescence measurements and theoretical calculations and simulations based on MOFs with well-defined structures, they found singlet exciton that migrates through the Förster mechanism jumping beyond nearest neighbors. One-step jumping over the long distance is slow, but it exponentially increased the number of possible paths, finally leading to the contribution from exciton jumping beyond the nearest neighbor accounting for a high proportion in the over energy transfer rates. This work thus presents a significant insight that will shape the design of highly efficient energy transport networks.

The work is performed by the Xiamen University master Qiongqiong Zhang, postdoctoral Cankun Zhang, Dr Lingyun Cao as the co-first authors. Cankun Zhang is undergoing postdoctoral joint training at Xiaoyu Cao’s group from Xiamen university. In this subject, other members of the Xiaoyu Cao’s group also helped with the synthesis of organic ligands. This work was financially supported by the National Natural Science Foundation of China (214711128), Thousand Talents Program and Xiamen University Funds for talents.

Paper link: http://pubs.acs.org/doi/abs/10.1021/jacs.6b01345