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Flexible photovoltaics systems are one of the initial applications of nanotechnology based on new organic polymeric materials.

In contrast to the conventional photovoltaics, the flexible photovoltaics can be placed anywhere, on top of the smallest surface possible (e.g. bags) or, on the other extreme end, to cover long queues for several kilometers.

They fold like paper, they are flexible, they offer energy independence and they have low cost. The secret lies in the complex organic films which constitute the heart of this new solar technology.

Mr. Panagiotis Karagiannidis PhD candidate of A.U.Th was awarded with the first young scientists award during the Symposium of European Materials Research Society in 2010, in Strasbourg, for his research. It mainly refers to the thermal annealing effect on the nanomechanical properties and structure of thin films of polymer-fullerene heterostructures, which are used as the active layer in organic photovoltaic for the light absorption and its conversion into electricity.

Thin, flexible and resistant organic photovoltaics


The semiconducting polymers in combination with fullerenes are perhaps the most promising materials for application in organic photovoltaics. They absorb sunlight and release electrons which are bound by fullerenes and are being promoted to the electric circuit. The efficiency of organic photovoltaic is directly connected to the structure and phase separation, while the nanocomposite mechanical properties affect the life of the photovoltaic element.

In this study, the effect of thermal annealing has been investigated (maintenance of the material at a certain temperature and for a certain period of time - thermal annealing) in the structure and morphology of the active blend. By using various Atomic Force Microscopy techniques (AFM) such as the Atomic Force Acoustic Microscopy technique (AFAM) and through the force - displacement curves, it enables the mapping the surface hardness of thin films and the study of their Nanomechanics behavior as well as the identification of the phases as they are generated by heat treatment. The two phases separation in a specific scale (?10 nm) plays a crucial role for high efficiency of OPVs provision. New characterization techniques are required for better characterization of these heterostructures in nanoscale. The combination of the Nanomechanical study with the X-ray diffraction is an alternative characterization methodology of these materials. However, there are still many steps to be taken in order to improve the efficiency and service life of the new organic photovoltaic cells.

European Materials Research Society, 2010

The award from the E-MRS concerns the research of the PhD candidate Panagiotis Karagiannidis from the School of Physics, A.U.TH, entitled ‘Thermal annealing effect on the nanomechanical properties and structure of P3HT:PCBM thin films’. The research took place at the Laboratory of Thim Films-Nanosystems & Nanometrology (LTFN) under the supervision of professor Stergios Logothetidis.

The E-MRS organizes scientific meetings, with around 2,500 participants each year, where the latest technological developments of functional materials are presented, aiming to promote the effective partnerships between industries and research laboratories, as well as cooperation with funding agents.


Panagiotis Karagiannidis, PhD Candidate A.U.TH.

Spyros Kassavetis, Postdoctoral Researcher A.U.TH., Charalambos Pitsalidis, PhD Candidate A.U.TH.

Head Research Team: Stergios Logothetidis, Professor at School of Physics A.U.TH., Scientific Responsible and Founder of the Laboratory of Thim Films-Nanosystems & Nanometrology (LTFN).