Researchers from The University of Queensland, EPFL, Griffith University and NIMS have studied how doping can help in overcoming some of perovskite solar cells' drawbacks. The researchers found that the efficiency and thermal stability of the doped cells significantly outperformed those that were not doped.

Cesium-doped Ti3C2Tx MXene for efficient and thermally stable perovskite solar cells image

“The PSCs that had doped cells showed a remarkable solar conversion efficiency that exceeded 21 per cent,” the team reported.

The research team prepared functionalized Ti3C2Tx MXene nanosheets doped with cesium (Cs) and introduced them into a lead iodide (PbI2) precursor solution for perovskite solar cells (PSCs) through a two-step deposition method, combining the advantages of both additives.

The team's theoretical and experimental analysis revealed that cesium plays an important role in improving perovskite crystallization and thus leads to enlarged crystal grains, long-lived carrier lifetimes, and reduced charge recombination compared with the devices fabricated without and with undoped Ti3C2Tx MXene.

PSCs integrated with cesium-doped Ti3C2Tx MXene deliver high photovoltaic efficiency of up to 21.57% with excellent thermal stability. The incorporation of Cs-Ti3C2Tx paves the way to further improvements of the photovoltaic performance and thermal stability of PSCs by indirectly introducing dopants.