Researchers have made a significant breakthrough in organic solar cell technology, addressing a key challenge that has hindered their efficiency and stability.
A group from Finland’s Abo Akademi University has cleared the path for organic solar cells to become more effective and durable by discovering and resolving a hitherto unidentified loss process. This could have consequences for future large-scale production.
Their research showed impressive progress with structure-inverted organic solar cells that were 1 cm² in area and had an efficiency of more than 18%.
Furthermore, under white light irradiation, the cells exhibited an unparalleled longevity of 24,700 hours. This corresponds to the longest longevity known for organic solar cells, with an estimated operational life of almost 16 years.
The Organic Electronics Research Group at Abo Akademi University produced the findings in cooperation with the group led by Professor Chang-Qi Ma at the Suzhou Institute for Nano-Tech and Nano-Bionics in China.
Earlier, Trina, a Chinese manufacturer, set a new world record for solar module efficiency with its large-surface n-type completely passivated heterojunction (HJT) modules achieving a 25.44% efficiency rate in lab tests.
The appeal of organic solar cells
Organic photovoltaics have gained attention due to their unique advantages. These cells are lightweight, flexible, and manufactured through energy-efficient processes.
Organic solar cells’ power conversion efficiency has dramatically increased over the last five years, with standard designs currently surpassing 20% in lab settings.
Notwithstanding these developments, problems with material deterioration brought on by exposure to air and sunshine, which affects long-term stability, prevent their widespread usage.
Researchers have looked into alternate designs, like structure-inverted, or n-i-p, solar cells, to overcome these difficulties. These designs are a possible alternative for longer-lasting solar cells because they put durability first by utilising more stable materials in the topmost contact layer.
However, studies claim that, historically, their effectiveness has fallen short of that of traditional designs.
Solving the loss mechanism
The team at Abo Akademi identified a critical issue in structure-inverted organic solar cells: the bottom contact layer, often made from metal oxides like zinc oxide, creates a narrow recombination area. This leads to a loss of photocurrent, reducing the cell’s overall efficiency.
To solve this problem, the researchers applied a thin layer of solvent-processed silicon oxide nitrate (SiOxNy) to the bottom contact. This passivation layer eliminated the recombination area, significantly improving both efficiency and stability.
In addition to addressing the loss mechanism, this novel methodology shows promise for incorporating this technique into the large-scale production of organic solar cells.
The team believes that organic photovoltaics have a lot of potential for sustainable energy solutions because of their lightweight and flexible design as well as their energy-efficient manufacturing.
By achieving record-breaking efficiency and lifespan, researchers believe that it is a significant step towards making organic solar cells a more practical and reliable choice for widespread use. “The work underlines the potential for using the method in the large-scale production of efficient and stable organic solar cells,” said the team in a statement.
The details of the team’s research were published in the journal Nature.