Guanidine Isothiocyanate New Skill Release: Auxiliary Surface Matrix Engineering Techniques

Guanidine isothiocyanate is widely used in the field of solar cells, which can improve the stability of new concept cells such as perovskite solar cells and increase the photoelectric conversion efficiency of batteries. Recently, scientists have "cracked" the new skills of guanidine isothiocyanate and found its new function in the field of solar cells, that is, auxiliary surface matrix engineering technology for efficient perovskite quantum dot photovoltaic materials.

The study, conducted by Wanli Ma's team at Soochow University in collaboration with researchers at the Federal Institute of Technology in Lausanne, Switzerland, uses guanidine isothiocyanate to initiate a ligand exchange process known as "LE-TA" after mild thermal annealing. This paper provides a ligand-assisted surface matrix strategy for engineering the surface and packing state of metal halide perovskite quantum dots (Pe-QDs) solids. The relevant results are published in the recent journal Advanced Functional Materials.

The researchers found that the surface matrix formed by guanidine isothiocyanate on CsPbI3 QDs is mainly composed of cationic guanidine (GA+) instead of SCN-, which allows it to maintain its intact cubic structure and promotes the interparticle electrical interaction between QD solids. In addition, through experiments, the CsPbI3 QDs of the GA matrix showed significantly enhanced charge mobility and carrier diffusion length, thus achieving the highest power conversion efficiency of 15.21% when assembled in photovoltaic, which is one of the highest power conversion efficiency of all metal halide perovskite quantum dots solar cells. Moreover, the ligand exchange process triggered by guanidine isothiocyanate has a similar effect when applied to other Pe-QD photovoltaic systems, such as CsPbBr3 and FAPbI3, demonstrating that the "LE-TA" method can regulate the versatility of multiple Pe-QD surfaces.

The new skill release of guanidine isothiocyanate in the field of new energy batteries may provide new guiding principles for the construction of conductive and structurally intact Pe-QD solids for efficient optoelectronic devices.

Reference: Xufeng Ling et al. Guanidinium‐Assisted Surface Matrix Engineering for Highly Efficient Perovskite Quantum Dot Photovoltaics, AM, 2020.

https://onlinelibrary.wiley.com/doi/10.1002/adma.202001906