Lead-free Metal Halide based Solar Cells

Sammanfattning: Lead-halide perovskites have recently appeared as very promising materials for solar cells. However, their stability and toxicity may be limiting factors for their application. Therefore, to find new low toxic and high stability light harvesters may be necessary for overcoming the challenges of perovskite solar cells. The overall aim of this thesis is to explore new low toxic light harvesters and to investigate their possibility for application of solar cells. The focus in the thesis is on bismuth halide-based light harvesters, which show high light absorption coefficient and promising photovoltaic performance. Specifically, the investigated materials are different compositions of metal halides in which silver, Ag or cesium, Cs, are combined with bismuth, Bi, or antimony, Sb and the halides iodide, I, or bromide, Br. All of the systems show very promising optical performances, however, their photovoltaic performances are still low, which is partially due to the recombination and defects issues, etc. Through adjusting the elemental compositions by mixing Bi/Sb or I/Br the optical properties were tuned. By varying fabrication conditions or devices architectures, the results in this thesis also show that all the low toxic light harvesters works in solar cells, which possibly can be utilized in future photovoltaics.