Salleo and McGehee groups from Stanford University Department of Materials Science and Engineering cooperated with multiple teams abroad for their latest project regarding how the electrons & holes split in organic solar cells.
Their work was published by Nature Materials on November 17th. Titled “Efficient charge generation by relaxed charge-transfer states at organic interfaces”, lead by Dr. Koen Vandewal from Salleo Group, the paper disproves the widely believed “Hot Exciton Effect” (click here to read the paper).
Hot Exciton Effect simply states that when a photon hits an organic cell and creates an electron & hole pair, called exciton, the separation of the two requires electron to have extra energy to break away from the hole. The experiments conducted at the Salleo Group’s lab showed that there was no need for extra energy for electron & hole pairs to split and that the Hot Exciton Effect just did not exist.
It is worth mentioning that the teams disprove the Hot Exciton Effect but do not provide a definite answer to how the electron & hole pair, exciton, splits in an organic solar cell. They do, however, strongly believe that the answer lies within the disordered arrangements in Polymers. This is consistent with the recent study Salleo Group published, as we covered in “Disorder in Polymers” team update (click here to read the update)
To learn more about the Salleo and McGehee groups from Stanford University Department of Materials Science and Engineering, please visit the respective team’s review below.