Imaging hybrid perovskites while minimizing damage

The adjustable band gap, excellent charge-transport properties, and low-cost solution processability of organic-inorganic hybrid perovskites show significant potential for use of these materials in photovoltaic cells and light-emitting diodes (LEDs). Transmission electron microscopy has proven effective in understanding the composition and electronic properties of the perovskites. However, radiation associated with electron microscopy can damage the structure of these pristine, photoactive materials.

Du et al. discussed damage resulting from microscopy and suggested a method for appropriate specimen preparation and characterization techniques of the hybrid perovskites.

“We believe that electron microscopy is a tool that has major potential to accelerate the understanding of perovskite solar cell materials,” said author Wei Li. “However, due to the inherent difficulties using the techniques, they are currently under-used.”

The authors focused on the damage process, stressing that awareness of the destructive changes resulting from electron illumination will allow researchers to successfully modify their microscopy methods.

They provided an overview of the general mechanisms of the damage induced by electron and ion beams then illustrated the structural modification experienced by the perovskites when subjected to irradiation. Previously, these adverse effects were mistakenly attributed to the intrinsic structure of the crystals.

The team described recently developed techniques that reduce irradiation-induced degradation, including cryogenic-focused ion beams and direct detection electron counting cameras. They conclude with a protocol for appropriate transmission electron microscopy specimen preparation and characterization techniques for hybrid perovskites.

“Our work brings together the latest knowledge about how to conduct electron microscope studies on the technologically important photoactive hybrid perovskite materials,” said Li.

Source: “Transmission electron microscopy studies of organic-inorganic hybrid perovskites: Advances, challenges and prospects,” by Hong-Qiang Du, Yang Jiang, Mathias Uller Rothmann, Udo Bach, Yi-Bing Cheng, and Wei Li, Applied Physics Reviews (2023). The article can be accessed at https://doi.org/10.1063/5.0142461 .

This paper is part of the Energy Storage and Conversion Collection, learn more here .