Understanding and controlling excitons, charges and defect states in new zero-, two-, and three-dimensional bismuth perovskite materials for optoelectronic applications

Time period:

1 January 2017 – 31 December 2020

Project leader:

Erik Johansson

Project member:

Michael Odelius

Funder:

Swedish Research Council

Type of award:

Project grant

Total funding:

3,400,000 SEK

Lead-halide perovskites have the recent years been developed for use in optoelectronic devices. In particular solar cells based on these perovskites have shown very high solar to electricity conversion efficiencies, and also lasers and photodetectors based on the lead-halide perovskites has shown very promising properties. However, one main concern with the lead-halide perovskites is the content of lead, which is toxic. We have last year discovered that a zero-dimensional bismuth-halide perovskite can replace the lead perovskite in solar cells with promising results. Bismuth is much less toxic than lead, and bismuth-halide perovskites may therefore be essential for the utilization of perovskites in optoelectronic devices on a large scale.In this project we will investigate the fundamental properties of the bismuth perovskite and also prepare new bismuth perovskites with zero-, two, and three-dimensional character. We will perform advanced measurements and theoretical calculations to investigate; how light is absorbed in these materials, the properties and dynamics of the excited electron-hole pair (exciton), the conduction of charges, and the nature and effects of defect states.We will also perform measurements on devices with the bismuth perovskites, and specifically focus on solar cells. We can therefore link the fundamental properties to the application in devices, which will be of key importance for further development of these materials and devices.