Research into limitations in new materials for perovskite solar cells
Perovskite solar cells, praised for their efficient conversion of light into electricity, are being studied as a promising next-generation solar technology. However, commonly used hole transport materials, such as spiro-OMeTAD, pose challenges due to their complex synthesis processes and high costs.
To address these issues, researchers have developed an alternative: HND-2NOMe, which is easier and more economical to synthesize.
The quasi-planar molecular structure of HND-2NOMe facilitates one-dimensional alignment and promotes charge transfer. Despite high charge mobility, solar cells using HND-2NOMe have shown performance limitations, including reduced current flow, the cause of which remained unclear.
Researchers from the University of Tsukuba used electron spin resonance (ESR) to investigate these performance challenges by analyzing the microscopic properties of the material. They found that holes migrate from the perovskite to HND-2NOMe without illumination, creating an energetic barrier at their interface.
This barrier hinders the movement of holes, contributing to the perceived performance issues. Furthermore, cells incorporating HND-2NOMe showed reduced hole accumulation under solar irradiation, which aided in the stability of the material’s hole transport function.
This identification of performance limiting factors, while maintaining stability, provides important insights for developing guidelines that can improve device performance. The research paves the way for future developments in perovskite solar cell technology.
Research report:Microscopic analysis of low but stable performance of perovskite solar cells using electron spin resonance.
