Domestic researchers have developed a technology to synthesize perovskite nanoparticles, which are gaining attention as next-generation semiconductor materials, more uniformly and efficiently. This is expected to help solve the limitations of existing synthesis methods and accelerate the commercialization of various optoelectronic devices, such as displays and solar cells utilizing nanoparticles.
Professors Kim Young-gi and Roh Yong-young from the Pohang University of Science and Technology (POSTECH) announced on the 19th that they developed a new synthesis method that precisely controls the size and shape of perovskite nanoparticles using liquid crystal solvents. The research results were published in the international academic journal "ACS Nano" on Jan. 14.
Perovskite nanoparticles can freely control the properties of light absorption and emission depending on their size and shape. Therefore, they hold great potential in next-generation solar cells and high-efficiency displays.
However, existing perovskite synthesis methods, such as 'hot-injection' and 'ligand-assisted reprecipitation', require high synthesis temperatures and complex experimental conditions, limiting the production of uniform-sized and shaped particles. Additional processes must be undertaken to obtain particles with the desired characteristics, which also reduces productivity.
The research team developed a synthesis method that precisely controls the size and shape of perovskite particles using liquid crystal solvents. Liquid crystals, which are in between liquid and solid, have elastic properties like springs, allowing them to return to their original shape when an external force is applied. The research team succeeded in controlling particle growth by changing only the solvent to liquid crystal while keeping the other synthesis conditions the same as in the existing 'ligand-assisted reprecipitation' method.
Particles stop growing due to the elastic force of the liquid crystal once they exceed a certain size within the liquid crystal. This allows for the mass synthesis of uniform-sized and shaped perovskite nanoparticles without the need for a separate purification process.
It was also discovered that the interaction between the particles that bind to the surface of perovskite nanoparticles, called 'ligands', and the liquid crystal molecules plays a crucial role in reducing surface defects. Liquid crystal molecules have elongated rod shapes, allowing ligands to be densely arranged between them. As a result, when nanoparticles are formed, ligands can bond more stably to the surface, minimizing surface defects and enhancing luminescent properties.
Professor Kim Young-gi noted, "The synthesis method developed this time has high compatibility with existing synthesis technologies and will enhance the performance of various AUK devices such as displays, solar cells, lasers, and photodetectors." He added, "Using this technology, it is expected that high-performance NANO nanoparticles can be produced uniformly in large quantities at room temperature, which will help accelerate the commercialization of NANO-based optoelectronic devices."
References
ACS Nano (2025), DOI: https://doi.org/10.1021/acsnano.4c13217