SolvenT-free, scalable dEposition of metaL haLide perovskites by mAgnetron sputteRing for high-efficiency solar cells

• Applicant: Iryna Galstian, Ph.D.
• Subject Area: Synthesis and Properties of Functional Materials ; Experimental Condensed Matter Physics ; Solid State and Surface Chemistry, Material Synthesis ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 554795821

Metal halide perovskites (MHP) have attracted considerable interest for a wide range of applications such as photovoltaics, light-emitting and laser diodes, and X-ray detectors due to their high absorption coefficient. They have high optical constants, high carrier mobility, long carrier diffusion range, and the unique ability to dynamically adjust the band gap, which is critical for semiconductor applications. The excellent optoelectronic properties of MHP are comparable to those of traditional inorganic semiconductors such as GaAs, but they are relatively easy and much cheaper to synthesize, making them attractive for mass production. Technical improvements in perovskite formulations and fabrication processes have led to significant improvements in energy conversion efficiency, but since perovskite operation is still relatively new, there is great opportunity for further research into the fundamental physics and chemistry surrounding perovskites. In addition, MHP currently face some challenges and limitations, such as low stability. All of this requires additional research and development to make perovskites viable for large-scale industrial use.The STELLAR project combines the technology-oriented research related to solution-free mechanosynthesis of powders with magnetron sputtered film deposition to produce stable hybrid organic-inorganic MHP, and the research on physical mechanisms underlining the exceptional properties of the investigated systems and the possibility of tuning them.Determining the role of precursor stoichiometry during mechanosynthesis, the influence of target preparation parameters and sputtering details on the properties of deposited films, studying their structure and spectroscopic properties will provide new information on the stability and degradation processes of hybrid organic-inorganic perovskites. Sputtered films will be deposited on glass/ITO/charge-coupled layer samples to determine optimal deposition parameters for forming films on different substrates that will later be used for solar cell fabrication.The surface morphology of both the targets and the resulting perovskite thin films as well as the surface and cross-section of the deposited thin films will be investigated. The roughness of the films, their composition and crystalline structure will be characterized, and the phase and orientation of the perovskite layer will be determined. The optical properties of films deposited from different targets will be determined and the energy disorder in the deposited layers will be evaluated as a function of structural properties. Taken together, the results of this work will allow us to obtain perovskite films of high optoelectronic quality and stability, as well as to understand the physical mechanisms that allow tuning their properties for rapid integration of such structures into advanced solar cells.

• DFG Programme: WBP Position