In recent years, thanks to considerable research efforts on perovskite (PVSK) -based solar cells (PSCs), their performance in small-area device has reached 26.1%, which is comparable to single-crystal silicon-based solar cells. However, for further development, PSCs need to achieve long-term stability. The intrinsically hygroscopic nature of PVSK materials is the main adverse factor affecting the stability of PSCs.

To overcome the hygroscopic nature of PVSK, quasi-2d PVSK has garnered attention from the scientific community due to its excellent environmental stability. However, the insufficient electrical properties of quasi-2d PVSK have caused inferior device performance compared to conventional PSCs, mainly due to the limited vertical charge transport and the presence of numerous defect sites in the PVSK, which act as charge carrier trapping sites. Here, the research team from Korea's Gwangju Institute of Science & Technology (GIST) successfully demonstrates efficient and stable quasi-2d PVSK-based PSCs by developing a novel zwitterion passivation strategy on the top surface of the PVSK.

The novel zwitterion-passivated quasi-2d PVSK exhibits a well-ordered vertical orientation and significantly reduces both surface and grain boundary defects, leading to efficient charge carrier transport in PVSK materials. Consequently, a high power conversion efficiency (20.05%) was achieved, along with excellent operational stability over 1,000 hours, retaining about 88% of the initial PCE under continuous 1-sun irradiation. Furthermore, the quasi-2d PVSK-based PSCs also demonstrate superior thermal and humidity stability. The research team firmly believes that their findings represent a genuine breakthrough, showcasing highly efficient quasi-2d PVSK-based optoelectronic devices, such as light-emitting diodes, thin-film transistors, and photodiodes. Their research was published in Advanced Materials on June 15, 2023.

The effects of a novel zwitterion passivation strategy in quasi-2D perovskite-based solar cells (left) and the long-term stability test of perovskite solar cells under various conditions (right)

[Reference] Kim J-H. et al., (2023) “Efficient and Stable Quasi‐2D Ruddlesden–Popper Perovskite Solar Cells by Tailoring Crystal Orientation and Passivating Surface Defects” Advanced Materials. DOI: 10.1002/adma.202302143.

[Main Author] Ju-Hyeon Kim (GIST), Heejoo Kim (GIST), Kwanghee Lee (GIST).

* Contact : Professor Kwanghee Lee (klee@gist.ac.kr)