Chen and co-workers examine internal conversion from the lowest lying charge transfer state to the ground state at a Tris(2,2'-bipyridine)ruthenium(II) 314.5 cm -1 2.769 5.75 × 10 6 s -1 1.17 × 10 7 s -1 pentacene to C 60 interface, and found multiple dependencies on the number of pentacenes surrounding the C 60 fragment, as well as their configuration (Figure ). In a herringbone configuration, rates would vary between 10 9 -10 11 s -1 for edge-on configurations, while the spread was much less for face-on configurations, between 10 10 -10 11 s -1 . Conversely, for co-facial configurations, face-on geometries peak at speeds of ∼10 10 s -1 for three pentacene chromophores, while edge-on geometries appear to continually increase in speed as the number of pentacenes increase, from 10 9 -10 11 s -1 . This behaviour was attributed to the interplay between the electronic energy gap and vibronic coupling term caused by hole delocalisation and consequential migration from the interface. Bhattacharya and co-workers examined donor-acceptor-donor Pechmann dye analogues, and found interfacial internal conversion rate constants ranging between 10 -4 -10 11 s -1 , depending on the employed substitution, highlighting the extreme sensitivity and control that can be elicited through the right kind of engineering. Zhao and co-workers performed a similar examination on a novel dithienyl-diketopyrrolopyrrole-selenophene donor and -phenyl-C 61 -butyric acid methyl ester acceptor system, and found an rate constant of 3.767×10