A collaborative research team led by Prof. Hyun Suk Jung from the Department of Advanced Materials & Science Engineering and the SKKU Insititute of Energy Science and Technology(SIEST) has successfully developed highly efficient and stable perovskite solar cells by utilizing perovskite-polymer composites.

Halide perovskite thin films often experience lattice distortion during crystal growth due to mismatches in the thermal expansion coefficients with the substrate, leading to residual stress within the film. This stress lowers the activation energy for ion migration, accelerating perovskite decomposition, which necessitates the development of related technologies to ensure stability. Additionally, halide perovskite materials are extremely vulnerable to moisture, making moisture stability a critical requirement for commercialization.

To address these challenges, Prof. Hyun Suk Jung’s research team has developed an innovative approach to overcome the instability of perovskite, which has been a major obstacle to the commercialization of high-efficiency solar cells.

The research team produced stable and high-efficiency perovskite solar cells by cross-linking amorphous perovskite films with acrylamide monomers through light irradiation. This method promotes crystal growth and cross-linking between crystals within the film, significantly enhancing the stability of the perovskite thin films. Notably, acrylamide monomers expand the grain size of the perovskite films, induce preferred crystal orientation, and the cross-linked layer protects the perovskite films from moisture-induced degradation.

The research team highlighted that the technology developed through this research not only improves the efficiency of perovskite solar cells but also achieves significant advances in long-term stability.

According to the study, the device fabricated using the proposed strategy achieved a power conversion efficiency (PCE) of 24.45% and an open-circuit voltage (V_OC) of 1.199 V, the highest V_OC reported in the field of halide perovskite solar cells with a TiO₂ electron transport layer. The device also demonstrated high stability in humid environments, retaining 80% of its initial performance after 700 hours, and excellent photostability, maintaining 80% of its initial performance after 1,008 hours.

Process of the control in crystal growth in perovskite films to produce high-quality films and of enhancement of the hydrophobic properties of the films

Additionally, the research team successfully fabricated a large-area PSC module using the proposed strategy. This module, with an active area of 33 cm², exhibited a high fill factor of 77.1%, a power conversion efficiency of 20.31%, and outstanding storage stability, demonstrating its potential for scaling up to large-area devices.

This research is of academic significance as it effectively addresses the issues of grain boundary defects and lattice distortion in halide perovskite thin films, thereby enhancing their commercialization potential.

Prof. Hyun Suk Jung explained, "This novel approach using acrylamide monomers can mitigate lattice distortion, control crystal growth in perovskite films to produce high-quality films, and enhance the hydrophobic properties of the films, thereby addressing the long-standing issue of moisture stability in halide perovskite materials. This technology holds promise for contributing to commercialization."

The research findings were published as a cover article in the top 3% international journal in the Energy and Fuels field, Advanced Energy Materials, on January 5, 2024.

※ Journal: Advanced Energy Materials

※ Title: In Situ Polymerization of Cross-Linked Perovskite–Polymer Composites for Highly Stable and Efficient Perovskite Solar Cells

※ DOI: 10.1002/aenm.202302743

※ Author list

- Corresponding Authors: Prof. Hyun-Seok Jung (Department of Advanced Materials & Science Engineering, Sungkyunkwan University / SKKU Institute of Energy Science and Technology(SIEST)), Gil-Sang Han (Korea Research Institute of Chemical Technology)

- First Author: Guo He (Ph.D. candidate, Department of Advanced Materials & Science Engineering, Sungkyunkwan University)

- Co-authors: Geon Woo Yoon (Ph.D. candidate, Advanced Materials & Science Engineering, Sungkyunkwan University), Zi Jia Li (China New Energy R&D Center), Dr. Yeonghun Yun, Prof. Sangwook Lee (Department of Materials Science and Engineering, Kyungpook National University), Dr. You-Hyun Seo, Senior Researcher Nam Joong Jeon (Korea Research Institute of Chemical Technology)