A Facile Strategy to Achieve Large Triplet Gap Based on Excited-State Aromaticity-tunable Five-memebered Ring

We have proposed a facile strategy to achieve large triple gap by manipulating the aromaticity and the transition properties of the low-lying excited states, then theoretically designed and experimentally verified a series of donor-bridge-acceptor based on partially conjugated five-membered rings with high aromaticity in T₁ state to meet the harsh energy conditions required for hot exciton materials and for singlet fission materials.