Multifunctional polythiophenes in photodiodes

Photoinduced charge transfer between conjugated polymers and C-60 has been extensively studied. This property can be used in photovoltaic devices poly mer/C-60 heterojunction, where the photogenerated excitons in the polymer c an be dissociated at the polymer/C-60 interface. Since the number of layers in the device had increased, two important aspects to consider are the thi ckness of each layer and the light reflection at the interfaces due to the difference in the values of the complex index of refraction of the material s that compound this multi-layered device. Choosing the right thicknesses f or the materials it is possible to maximise the optical electric field near the dissociation region and then improve the efficiency of the device.