Triplet excitons in organic photovoltaics can redissociate via the charge-transfer state into free carriers, reducing losses and improving efficiency. This mechanism is enabled by molecular design controlling singlet–triplet energetics through exciton delocalization.

The study demonstrates that by tuning the energy gap between singlet and triplet states to within 0.1 eV, triplet recycling efficiency can reach 75%, boosting overall device performance to a record 19.6% power conversion efficiency for single-junction organic solar cells.