Lithium fluoride calcium cathode

The electrons for the radical anions are injected by the cathode, consisting of a metal with a low work function. Usually, calcium, a coevaporated magnesium-silver alloy with a Mg Ag ratio of 10 1, or aluminum can be used. The corresponding work functions are 2.9 eV, 3.7 eV, and 4.3 eV, respectively. The injection of the electrons can be facilitated by an additional layer of lithium fluoride [40]. Several mechanisms have been proposed to explain the electron injection improvement [41,42]. The most plausible mechanism is the dissociation of LiF toward metalHc hthium, which acts as a redox dopant for the electron-transport layer. From the cathode the electrons are then transported through the electron- transport layer on the LUMO level via hopping transport, which is in principle a mutual solid-state redox reaction. 

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