Image 1 (IMAGE) The University of Hong Kong Caption Image 1. The singlet fission process in pentacene dimer: the initial singlet exciton S1S0 of one monomer splits into two free triplet excitons T1-T1 via a correlated triplet pair 1(TT) equally spreading over two neighbor monomers. Singlet fission realises the down-conversion of photon energy and has become one of the focal areas in modern photovoltaic studies. Credit The University of Hong Kong Usage Restrictions This work is licensed for non-commercial, non-exclusive, one-time usage with attribution to the copyright holder. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.