Influence of the carbazole moiety in self-assembling molecules as selective contacts in perovskite solar cells: interfacial charge transfer kinetics and solar-to-energy efficiency effects

The use of self-assembled molecules (SAMs) as hole transport materials (HTMs) in p-i-n perovskite solar cells (iPSCs) has triggered widespread research due to their relatively easy synthetic methods, suitable energy level alignment with the perovskite material and the suppression of chemical defects. Herein, three new SAMs have been designed and synthesised based on a carbazole core moiety and modified functional groups through an efficient synthetic protocol. The SAMs have been used to understand the SAM/perovskite interface interactions and establish the relationship between the SAM molecular structure and the resulting performance of the perovskite-based devices. The best devices show efficiencies ranging from 18.9% to 17.5% under standard illumination conditions, which are very close to that of our benchmark EADR03, which has been recently commercialised. Our work aims to provide knowledge on the structure of the molecules versus device function relationship. The linker and the terminal functional groups of SAMs based on the carbazole core play an important role in the efficiency of inverted perovskite solar cells.

Automated summary

This article introduces the research progress of using self-assembled molecules as hole transport materials in perovskite solar cells. Three new self-assembled molecules have been designed and synthesized, and their interface interactions with perovskite and the impact on device performance have been studied. The efficiency of the best device is close to the benchmark commercial device, providing important insights into the relationship between molecular structure and device function.