Excitonic Conversions in Semiconductors

We studied the influence of parameters that govern the excitonic conversion phenomena in semiconductors. In this study we defined a surface conversion velocity of excitons to free electron-hole pairs b_s and a parameter of exciton dissociation in the space charge layer b (x) related to the electric field E(x). The influence of b_s on the electrons and excitons densities and on the short-circuit current shows that this parameteris a generation term for electrons and a recombination term for excitons. In the organic semiconductor where the excitons have a very short lifetime and a binding energy superior to thermal energy, an exciton conversion model is essential to increase the performance of these solarcells. Our study showed that the short circuit current has a high value when the exciton conversion speed is of the order of 10⁴ cm.s^-1.