Researchers from South Korea’s Ulsan National Institute of Science and Technology (UNIST) have reported a conversion efficiency of 25.17% in a perovskite solar cell, achieved by minimizing the deformation for the microstructure of photoactive layers in the device.

The inner structure of the newly-developed photoactive layer, as well as the working principle of the perovskite cell imageThe inner structure of the newly-developed photoactive layer, as well as the working principle of the perovskite cell. Image: Unist

The team explained that the microstructure of these layers, which generate an electric charge and send it to electrodes, can be deformed - which affects the efficiency of the charge transfer itself. “This is because the extracted electric charges disappear when defects are formed,” they explained.

The researchers say they have succeeded in minimizing the internal defects of the photoactive layers by changing the type and ratio of ions embedded in the layers. These changes were responsible for increasing the solar cell's open-circuit voltage, “Encapsulated devices retained 90% of their initial efficiency after 400 hours of maximal power point operating conditions,” the researchers stated, adding that the certified efficiency of the device is 24.4%.

The Korean team also stated that the cell maintained over 80% of its initial efficiency after 1,300 hours in the dark at 85 degrees Celsius.

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