The market for organic photovoltaics (OPV) has shown some growth in recent years, with particular interest being paid to the potential for building integrated photovoltaics (BIPV) and off-grid power charging systems. However, there are hurdles to be overcome; the greatest challenges facing OPV developers remain lifetime and efficiency. Overcoming these issues will be the key to the ultimate widespread commercialization of OPVs.

Heliatek GmbH develops and synthesizes small organic molecules - oligomers, and uses the deposition of these molecules in a low temperature, roll-to-roll vacuum process. Last year, the company signed a development agreement with AGC Glass Europe, the European branch of AGC, the world’s largest producer of flat glass, to develop BIPV by integrating organic solar films in glass to collect solar energy. Dr. Thomas Bickl, vice president sales and product development for Heliatek GmbH, said that reaching the market quickly is essential to success.

“The speed of market penetration will be key for our success,” Dr. Bickl said. “We need to convince enough customers in a so far commodity solar market so that we pick up enough momentum to become visible in the market.”

The Centre for Process Innovation (CPI) is conducting research into OPV production. Alf Smith, business development manager for CPI, noted that there are still a number of scale-up challenges for the technology to overcome before OPV reaches mass market production.

“There is a need for low cost and robust encapsulation solutions, with in-use weatherability the main obstacle to overcome,” Smith said. “Oxygen, water, UV and temperature degradation remain constant thorns in the development of OPVs. Across many application areas the development of low cost, high performance barrier coatings is a key requirement.”

Michael Niggemann, chief technology officer for Eight19 Ltd., Cambridge, UK, noted that bringing a new technology to market is a challenging endeavor.

“Improvements in efficiency, a longer life time and low cost are important aspects of our product development,” Niggemann said. “All these factors are not only affected by the availability of materials, but also by the choice of the right material combinations and the choice and development of the appropriate production processes.

“Eight19 is ideally suited to address these challenges with its significant investment in production equipment and personnel,” he added.
“A close collaboration with materials suppliers to jointly overcome these challenges is key. In practice, Eight19 has to evaluate a large number of materials, ranging from substrates, electrodes, interface materials and photoactive composites to encapsulation materials, adhesives, etc. Some materials are commercially available, while others are still in development.

“We have set up highly efficient fabrication processes for small flexible solar modules,” Niggemann noted. “In combination with a fully automated characterization capability using multiple test methods, Eight19 can evaluate materials and optimize processes in a highly effective way. Suppliers also benefit from our feedback for their internal product development.”

Being able to produce OPVs on a commercial level is also critical.

 “Up-scaling to large volumes in order to reach the necessary price points requires commitment from both OPV manufacturers and materials suppliers,” Niggemann said. “High volume production requires scalable solar module architectures, scalable production processes and high volume production machinery. Eight19 has developed proprietary device architectures and manufacturing processes that are highly compatible with state-of-the-art roll-to-roll production machinery. Some of the fabrication steps can be carried out using externally available capacities. This is a key approach to keeping the cost down while up-scaling to larger volumes.”