Compensating for the "weaknesses" of mixed perovskite materials with a 1+1 tandem structure.
Efficiency is approaching commercialization by absorbing both visible and near-infrared light.


A domestic research team has developed an inorganic perovskite solar cell with an efficiency of 18%, close to the 20% threshold for commercialization.

Professor Jang Seong-yeon's team from the Department of Energy and Chemical Engineering at Ulsan National Institute of Science and Technology (UNIST) announced on the 22nd that they have developed a hybrid solar cell using heterogeneous materials. This has increased efficiency from the existing 12.5% to 45%, bringing commercialization closer.

This is a "1+1" technology that links inorganic perovskite solar cells with polymer solar cells of different properties. Efficiency is improved by having the polymer material absorb the near-infrared region of sunlight, which the inorganic perovskite material cannot absorb.

Using inorganic perovskite as a light-absorbing material (photoactive layer) allows the creation of solar cells with much better thermal stability than conventional organic-inorganic mixed perovskite materials. However, when solar cells are made with this material, the efficiency is lower than that of general organic-inorganic mixed perovskite materials.

The research team complemented the weaknesses of inorganic perovskite solar cells by using two types of light-absorbing layers together. A '1+1 tandem structure' battery was created by connecting 'perovskite sub-cells' and 'polymer material sub-cells' in series vertically.

The principle is that perovskite unit cells absorb the visible light range of sunlight, and polymer material unit cells absorb the near-infrared range.

Professor Jang explained, “Through optical simulation, we were able to design perovskite and polymer materials with complementary solar absorption regions, and significantly increase efficiency by minimizing the ‘voltage loss’ that occurs when combining two unit cells.”

In particular, the newly developed perovskite-polymer hybrid tandem solar cell can be easily manufactured entirely using a "low-temperature solution process." Therefore, it is advantageous for mass production and offers lower manufacturing costs compared to existing silicon solar cells.

Professor Jang Seong-yeon said, “The hybrid tandem solar cell developed this time has applied technology that maximizes the advantages of each material,” and expressed his expectation, saying, “Through this, we will be able to develop high-efficiency and high-stability inorganic perovskite-based solar cells with an efficiency of over 28% in the future.”