Researchers at South Korea’s Ulsan National Institute of Science and Technology (UNIST) have developed a perovskite solar cell (PSC) by using alkylammonium chloride (RACI) to control the formation of defects in the perovskite layer.

The researchers said when testing the film in a perovskite cell, it was found that it achieved a power conversion efficiency of 26.08%, which exceeds the efficiency of silicon solar cells.

When tested by NREL experts, the device achieved a certified efficiency of 25.73%.

The study “Controlled growth of perovskite layers with volatile alkylammonium chlorides” was recently published in Nature.

The team has unveiled a novel method and principle for controlling the crystallinity of perovskite photoactive layer semiconductors and developed a technology to manufacture high-efficiency PSCs.

For high efficiency of PSCs, it is crucial to control the defects which have a significant impact on the long-term stability of solar cells.

Control of the generation process of thin films and understanding of the principles of this process are key factors that help achieve high efficiency and long-term stability at the same time, researchers said.

“Alkylammonium chloride, which is dequantized at the crystallization stage while combining with perovskite components, was used,” said researcher Sang Il Seok.

This optimal combination with Alkyl was also able to control the rate of volatilization with solvent during the coating and heat treatment of perovskite precursor solution.

The combination made it possible to manufacture a perovskite thin film that is dense but has a flat surface and minimizes internal defects of the crystal.

The researchers said through this study PSCs with more than 26% efficiency will soon surpass the efficiency of silicon solar cells, and it is the starting point of the journey to achieve more than 27% efficiency.

Recently, an international team of researchers developed a new technique to enhance the durability of inverted perovskite solar cells, which can be an essential step toward commercializing emerging photovoltaic technology and significantly reducing the cost.

In January, researchers at the Helmholtz-Zentrum Berlin said that they had produced PSCsto achieve efficiencies of well above 24%, which are resistant to drop under rapid temperature fluctuations between -60 and +80 degrees Celsius over one hundred cycles.