Professor Hong Seok Lee (Department of Physics, Research Institute of Physics and Chemistry, Chonbuk National University) and his team have developed a technique for manufacturing perovskite film 100 times the luminous efficiency.

The researchers produced a highly crystalline perovskite film by treating it with a solvent vapor of various polarities. They also developed a method to control the emission wavelength and efficiency by controlling the crystal size in the film according to the exposure time to the polar solvent vapor.

Perovskite is a material of excellent productivity due to its easy solution process and high electric conductivity. It has gained attention as a luminescent material for next generation display. However, the biggest obstacle that the material has is it’s a large crystal size in the micrometer level and the electrons and holes involved in luminescence easily disappear, not combining together.

To overcome the disadvantages, Lee’s team re-crystallized the perovskite film produced by the solution process with a polar solvent vapor. Through the recrystallization, they could reduce the crystal size to the nanometer level, and improve the crystallinity of the material by inducing the reaction of PbBr2 and CH3NH3Br, which are the unreacted precursors remaining inside the film. This method increases the luminous efficiency of the perovskite film by more than 100 times.

The research was made possible with the participation of Sang-Hyun Chin (Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, and Department of Physics, Chonbuk National University), Jin Woo Choi (Advanced Photonics Research Institute, Gwangju Institute of Science and Technology), Hee Chul Woo (Advanced Photonics Research Institute, Gwangju Institute of Science and Technology), Jong H. Kim (Department of Molecular Science and Technology, Ajou University), Hong Seok Lee (Department of Physics, Research Institute of Physics and Chemistry, Chonbuk National University) and Chang-Lyoul Lee (Advanced Photonics Research Institute, Gwangju Institute of Science and Technology).

Recently the study results were selected as the cover story for a recent issue of Nanoscale, a worldwide scientific journal in the field of chemistry.