A new attempt to stably obtain hydrogen without emission of carbon dioxide using perovskite solar cells one of the candidates for next-generation solar cells was introduced

※ Perovskite: The name of the crystal structure of minerals (ABX3) discovered by Russian mineralogist Lev Perovski (1792-1856) in 1839. Not only can it be absorb large area of light but it also has high absorption so it is widely used as a material for solar cells.

The National Research Foundation of Korea (Chairman Jeong-hye Noh) announced that the research team of Professor Sang-han Lee and Gwang-hee Lee (Gwangju Institute of Science and Technology) has confirmed that effective and stable hydrogen production is possible with perovskite internal defect control and liquid metal sealing technology.

Although there have been studies to produce hydrogen with perovskite solar cells (water electrolysis and photoelectrochemical water decomposition) perovskites ionic defects and susceptibility to moisture were obstacles.

※ Ion defect : It is a foreign material inside the crystal material which carries electric charge.

※ Water electrolysis : A method of producing hydrogen molecules (H2) and oxygen molecules (O2) by electrolyzing water molecules (H2O).

※ Photoelectrochemical water splitting : A method of producing hydrogen and oxygen by decomposing water molecules with electricity generated from light.

The research team supplemented the ionic defects of perovskite itself by using L-proline a type of amino acid as an additive.

L-proline which can have both positive and negative ions under certain conditions improves the efficiency and stability of the device by filling all of the cation defects and anion defects inside the perovskite.

※ L-proline : As one of the 20 amino acids that make up a protein it has both functional groups amine and carboxyl. According to liquids pH the electric charge that functional groups possess changes.

※ Zwitterion : An ion that has both positive and negative ions in one molecule.

In addition the vulnerability to moisture was solved by sealing the perovskite with indium gallium liquid metal and titanium foil.

Not only was it not affected by moisture but it was also possible to further increase the efficiency of hydrogen production by increasing the transfer of electric charge between the electrode and the device.

In fact the device made in this way has more than twice the stability of the conventional perovskite photoelectrochemical device and the hydrogen production efficiency (half cell efficiency) is also 9.6% which is the best performance among photoelectrochemical devices using perovskite materials.

The research team is planning to conduct research on perovskite materials for more stable hydrogen production in the future and catalyst research to lower production costs.

The results of this research within the support of the basic laboratory project (global laboratory project) the original technology development project (climate change response technology development project) and the basic research project (mid-level research) implemented by the Ministry of Science and ICT and the National Research Foundation of Korea. It was published online on January 21 in the international academic journal Advanced Functional Materials.