Sulfonium cations for quasi-2D perovskite solar cells

• Ruddlesden-Popper-type (RP) quasi-two-dimensional (2D) perovskite solar cells (PSCs) have actually brought in comprehensive focus due to their unique photovoltaic or pv properties and also exceptional device security. Due to disordered crystallization, the film quality of RP perovskite remains unsatisfactory.

To achieve better photovoltaic efficiency, various methods focusing on crystallization guideline have been applied. At present, associated study concentrates on the photovoltaic or pv residential or commercial properties of perovskite films after crystallization guideline, while the understanding of the crystallization process is lacking.

Just Recently, Prof. Zhou Huiqiong's group from National Center for Nanoscience and Technology (NCSNT) of the Chinese Academy of Sciences (CAS) has established a sulfonium cations-assisted intermediate design technique to research the evolution of intermediates and the film residential or commercial properties of quasi-2D perovskites. The research study was published online in Advanced Materials.

The researchers created an accomplished strategy for intermediate engineering by employing sulfonium cations to control the makeover of intermediates during the crystallization process and also boost the film quality of quasi-2D perovskites.

The intermediates were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to reveal the make-up and also makeover process of the intermediates. The intro of sulfonium cations prevented the formation of unfavorable solvated lead iodide as well as advertised the formation of beneficial perovskite intermediates with fiber-like morphology, which contributes to the formation of high-quality perovskite crystals. The above results have been validated in quasi-2D perovskite with various n values as well as 3D perovskites.

They then performed in-situ photoluminescence spectroscopy (PL) to study the crystallization throughout the film formation procedure. It was found that the intro of sulfonium cations could not just increase however also enhance the crystallization procedure, resulting in high-quality perovskite films.

Based upon the above results, regulating the properties of intermediates is a reliable method to acquire high-quality perovskite films. With enhanced film quality, the tool accomplished a power conversion efficiency of 19.08% at area temperature level as well as 20.52% at reduced temperature (180 K). On top of that, the matching devices showed improved operational stability, with 84% of the first efficiency maintained after 1000 h under maximum power point (MPP) tracking at 40 ℃.

"The thorough understanding of the advancement of intermediates enables us to clarify the mechanism of the boosted film quality through sulfonium cations treatment, and also the findings of this research will certainly benefit the future study on the crystallization guideline of perovskite solar cells," stated Prof. Zhou.