HELIOS

The industrial large-scale production of organic solar modules (OPV) is imminent in Europe especially in France. Organic solar cells have many advantages. They are large-area printed at low-cost from processes at room temperature. They have conversion efficiencies of photovoltaic records beyond 10% and thus represent an emerging PV technology competitor to inorganic thin-film amorphous silicon in particular. OPV allows energy footprints much shorter than those of all other inorganic PV technologies. We are talking about energy payback times of a few months only. However, the lifetime of OPV modules is to date still a challenge and research and development efforts are required on this topic. To improve the lifetime of a solar cell, there must be a good encapsulation and / or provide materials as stable as possible against the photochemical stress. It is also essential to stabilize the layers nano-sized morphology of the bulk heterojunction (BHJ), a key-parameter to efficient PV. Such a morphology is so far very thermally unstable. The proposal therefore focuses on these specific issues with the stabilisation of the nano-sized morphology to retain initial PV performances for roof-top applications. HELIOS aims to produce prototypes of OPV modules based on technology of chemical crosslinking recently invented during a previous project, the project CEPHORCAS (ANR-HABISOL-2010-003). Crosslinking allows the attachment by covalent bonding of semiconducting molecules in order to reinforced the material. By controlling the involved chemical processes, no loss of performance is caused by crosslinking. By cons, crosslinking enhances stability of two parameters, first the nano-sized morphology of the BHJ layer, and secondly the photostability of the organic material. Therefore, the crosslinking technology significantly increases the lifetime of OPV cells versus thermal and / or photochemical stresses. Academic partners AM2N-ICG (Montpellier) and MOLTECH-Anjou (Angers) are chemists and will work on the development of new compounds that are crosslinking additives to be added universally in any semiconductors. Following CEPHORCAS, we want to develop more efficient stabilizing additives exhibiting additional features. First, the additives will also enhance the self-organization of the morphology of the BHJ to facilitate the deposition technique. Second, stabilizing additives will be modified to become photo-active. Using a finely tuned antenna effect, they may participate in the collection / conversion of solar photons enabling improved PV efficiency. The crosslinking processes, fabrication and characterization of OPV cells will be studied IMS (Bordeaux). ICCF (Clermont-Ferrand) study the photochemical and thermal aging of materials and solar cells. HELIOS is an industrial project in which Solvay provide high efficiency PV polymers and will focus on the large-scale production of stabilizing additives and their toxicity. ARMOR will manufacture large-area prototypes using flexible technologies incorporating crosslinking agents. These modules will be tested and aged over several geographical sites in real sun exposure in outdoor conditions. SOLVAY and ARMOR will together develop an appropriate formulation of OPV inks. HELIOS will enable the industrial production of OPV modules with high power conversion efficiencies (cell> 9%, module> 7%) with increased lifetimes.