Multifunctional polythiophenes in photodiodes

Photoinduced charge transfer between conjugated polymers and C60 has been extensively studied. This property can be used in photovoltaic devices polymer/C60 heterojunction, where the photogenerated excitons in the polymer can be dissociated at the polymer/C60 interface. Since the number of layers in the device had increased, two important aspects to consider are the thickness 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 materials that compound this multi-layered device. Choosing the right thicknesses for the materials it is possible to maximise the optical electric field near the dissociation region and then improve the efficiency of the device.