Guanidine Isothiocyanate-Assisted Surface Matrix Engineering for Highly Efficient Perovskite Quantum Dot Photovoltaics

Guanidine isothiocyanate has a wide range of applications in the field of solar cells, which can improve the stability of new concept batteries such as perovskite solar cells and improve the photoelectric conversion efficiency of the batteries. Recently, scientists have discovered a new function of guanidine isothiocyanate, which assisted surface matrix engineering for highly efficient perovskite quantum dot photovoltaics.

This research was carried out by the team of Wanli Ma of Suzhou University and the researchers of Swiss Federal Institute of Technology in Lausanne, Switzerland. A ligand-assisted surface matrix strategy to engineer the surface and packing states of Pe-QD solids is demonstrated by a mild thermal annealing treatment after ligand exchange processing (referred to as “LE-TA”) triggered by guanidinium thiocyanate.

The researchers found that the surface matrix formed by guanidine isothiocyanate on CsPbI₃ QDs is mainly composed of cationic guanidine (GA⁺) rather than SCN^-, which keeps the complete cubic structure and promotes the interparticle electricity between QD solids interaction. In addition, through experiments, the CsPbI₃ and QDs of the GA matrix show significantly enhanced charge mobility and carrier diffusion length, so that the highest power conversion efficiency of 15.21% can be achieved when assembled in photovoltaics, which is all metal halide calcium titanium One of the highest power conversion efficiencies in mine quantum dots. Moreover, the ligand exchange process triggered by guanidine isothiocyanate has similar effects when applied to other Pe-QD photovoltaic systems (such as CsPbBr₃ and FAPbI₃), which proves that the "LE-TA" method can adjust a variety of Pe-QD The versatility of the QD surface.

The release of guanidine isothiocyanate's new skills in the field of new energy batteries may provide new guidelines for the construction of conductive and structurally complete Pe-QD solids for high-efficiency photovoltaic devices.

References:

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