Hanbat National University Researchers Refine 2D Perovskite Design

The research team, led by Professor Ki-Ha Hong, addressed a long-standing hurdle in materials science: the complex relationship between screening environments and excitonic properties in 2D perovskite thin films. While these materials show immense promise for optoelectronics due to their superior stability, the interplay between quantum confinement and surrounding layers has historically eluded precise control. To solve this, the team used a series of organic spacers with varying alkyl chain lengths, allowing them to adjust the dielectric environment without introducing structural interference.

Using photoelectron and UV-vis absorption spectroscopy, the team observed that increasing spacer length widens the quasiparticle bandgap while keeping exciton energy largely stable, which leads to a significant increase in exciton binding energy. Because the traditional Keldysh model proved insufficient to map these results, the researchers developed a phenomenological dielectric function that accounts for the finite thickness of the organic spacers. Published in Advanced Functional Materials, this validated framework provides engineers with specific design rules to manipulate exciton binding energy, offering a clearer path toward high-performance, tunable optoelectronic devices.