Contatto di riferimento: Laura Basiricò
Partecipanti: Dott. Tessarolo
In the field of Photovoltaic technologies the organic solar cells are particularly attractive because of their ease of processing, mechanical flexibility and potential low cost production techniques.
So far, the reported efficiencies are not high enough to allow to be competitive in the market, however with the introduction of new photoactive materials, device architectures and light management structures, the power conversion efficiencies, at laboratory scale, has rapidly reached the 12%, showing a great potential and a bright future for organic solar cells. Nevertheless, in view of commercial products, two main problems are still unresolved: the relatively low performance of the modules and their short lifetime.
In sight of this, promising approaches to further optimize the polymer’s opto-electrical properties, and thus the corresponding device performance, are presented. However, for the commercialization, a high efficiency is not enough if the solar cell is unstable, thus a deep investigation on device degradation processes is mandatory in order to preserve the performance.
On the one hand the thermal stability issue was investigated, and it has been demonstrated that, beside the active layer degradation, also the other layers and interfaces are critical for the solar cell thermal stability. In this contest an innovative fast capacitance based thermal test has been developed in order to obtain information regarding the limit operating temperature above which the device becomes thermally unstable.
On the other hand, a preliminary study on the photostability issue was carried out demonstrating that the photodegradation of organic solar cells not depends just on the photostability of the donor polymer, but is connected also with the composition of
the active layer solution and on the interaction with the adjacent layers. Solutions to limit or prevent the devices degradation processes are proposed.