Record-Breaking Organic Solar Cell Operates for Nearly 16 Years in Finland

Researchers have achieved a significant breakthrough in organic solar cell technology, addressing a key challenge that has previously hindered their efficiency and stability.

Eliminating Energy Loss Mechanisms

A research team at Åbo Akademi University in Finland successfully identified and resolved a long-standing issue that had been limiting the advancement of organic solar cells. According to a report by Interesting Engineering, their discovery could have profound implications for large-scale manufacturing in the future. Their work focused on structurally inverted organic solar cells, with an active surface area of 1 cm², achieving an efficiency of over 18%.

Under white light irradiation, these solar cells demonstrated an unprecedented operational lifespan of 24,700 hours—equivalent to nearly 16 years—the longest ever recorded for organic solar cells.

This milestone was accomplished by Åbo Akademi University’s Organic Electronics Research Group in collaboration with Professor Chang-Qi Ma’s team at the Suzhou Institute of Nano-Tech and Nano-Bionics in China.

Previously, the highest efficiency recorded for a solar module was achieved by China’s Trina Solar, which developed n-type fully passivated heterojunction (HJT) modules with a laboratory efficiency of 25.44%.

Advantages of Organic Solar Cells

Organic photovoltaic technology is gaining increasing attention due to its unique benefits. These solar cells are lightweight, flexible, and can be manufactured using energy-efficient processes.

Over the past five years, the power conversion efficiency of organic solar cells has seen a significant increase, with standard designs now exceeding 20% in laboratory conditions. However, challenges persist due to the degradation of organic materials caused by exposure to air and sunlight, limiting their long-term applicability.

Researchers have been exploring alternative architectures, such as inverted-structure solar cells, which incorporate more stable materials in the top contact layer to enhance durability. However, their efficiency has historically been lower than that of traditional designs.

Overcoming Energy Losses with Innovative Solutions

The Åbo Akademi team identified a crucial issue in inverted-structure organic solar cells: the bottom contact layer, often made from metal oxides like zinc oxide, created a narrow recombination zone, leading to photo-current losses and reducing overall circuit efficiency.

To address this, researchers applied a thin, solvent-processed silicon oxynitride (SiOxNy) passivation layer to the bottom contact layer. This innovative approach eliminated the recombination zone, significantly improving both efficiency and stability.

Moreover, this new solution opens the door for large-scale production of organic solar cells. By enhancing their efficiency, durability, and manufacturability, researchers have paved the way for a sustainable energy source characterized by lightweight construction, flexibility, and cost-effective production.