OPV manufacturing process
The materials used for the fabrication of OPVs are predominantly carbon based with no rare or toxic elements included. These organic compounds act as building blocks for the solar cells and can be easily and cost effectively synthesized in large quantities and high quality. The chemical and physical properties of the organic materials and therefore the OPV characteristics can be furthermore tailored to the customer’s demands and expectations. This assures a wide range of application possibilities for the OPVs, due to their adjustable colour, shape, and viable power output.
The organic materials used for the manufacturing processes of the OPVs are solubilized. Their deposition, therefore, can be accomplished by means of common printing techniques, avoiding expensive vacuum based techniques and high temperatures. Similar to the printing of newspapers and magazines, OPVs can be fabricated on thin plastics at a high throughput on a continuously moving roll-to-roll web. The extremely low energy consumption during the manufacturing process compared to their inorganic silicon counterparts, leads to a very low carbon footprint. At the end of their life, some of the materials within the OPV structure can be recycled and reused, while the OPV laminates can be disposed. These factors show that the OPV technology allows a material, energy, and carbon savings from “cradle to grave” and represents a truly green renewable energy solution.
Since organic photovoltaics can be integrated into nearly every surface and product, due to their mechanical flexibly, low weight, and possible semi-transparency, the manufacturing process will be adapted to the customer’s requirements. Nevertheless, these steps are important:
As shown above, firstly the substrate carrier has to be prepared for the sequential deposition of the OPV layers. For this step, lasers are used to structure the bottom transparent electrode on top of the substrate, allowing the creation of OPV base with numberless shapes, some of which are shown above. Then, the layers of the OPV are deposited using printing techniques, allowing easy scalability of the solar cell’ size. OPVs with different colours are also possible. The top electrode deposition follows, and is required to complete the OPV device. The design of the top electrode can be chosen by the customer, and can represent a particular figure or a logo. At the end, the OPV is encapsulated to assure long term operational stability.
Energy Payback Time
The use of low cost materials as building blocks for the OPVs, in addition to the high speed fabrication process at low temperatures, allows short energy pay back times. Some key advantages of the technology are:
- No rare earth materials needed
- Short energy payback time less than 3 months
- OPV laminates do not contain toxic materials
- The energy for the final product is ten times smaller than that for silicon-based PV
- One can rely on established recycling processes
Today hydropower is defining the Eco-Efficiency Frontier. OPV operates at the same level of eco-efficiency as hydropower.