Morphological and structural interface characterization in multilayer inverted polymer solar cells

The interfaces in multilayer inverted polymer solar cells based P3HT / PCBM bulk heterojunction were prepared and studied on a flexible polyethylene naphthalate (PEN) substrate. The annealing effect on each interface of the PEN/ITO/ZnO multilayer and also ZnO/P3HT:PCBM on the structural, photophysical and photovoltaic properties was investigated and scrutinized directly on OPV device using the tomographic atom probe (TAP), scanning electron microscope (SEM) and microfocus X-rays techniques. We carried out a three-dimensional reconstruction of each interfaces of the multilayer containing PEN/ITO, ZnO/ITO and P3HT: PCBM/ZnO to analyze interface property and its influence on the morphology of the photoactive film. These analyzes provide strong evidence that the morphology of the interfaces induced by the modification of the structure of each layer of the BHJ devices leading to an anisotropic morphology and good orientation of P3HT crystals with PCBM Aggregates and ZnO and thus to lead to a significant change of Characteristics of photovoltaic devices.