Dr Malin Johansson: Metal halide perovskite solar cell properties: From macro to nano scale
Read a blog detailing the key takeaways here.
Availability and intensity of solar radiation varies by location and time. However, solar energy is free of cost and most abundant of all renewable energy sources. Photovoltaics can convert the solar energy directly into electrical energy with low environmental impact during operation. The current manufacturing routes and the recycling conflicts with many of the environmental goals. Therefore, more detailed studies to avoid negative environmental impact are of importance to find sustainable solutions for future energy conversion.
Metal halide perovskites are semiconductors that have attracted much attention because of their high absorption, efficient charge separation and long charge carrier lifetime. Despite high defect levels, in the order of 10 15 cm -3 in polycrystalline metal halide perovskite thin films, perovskite solar cell devices operate remarkably well, now reaching 25.7% efficiencies. Perovskite can also be grown as single crystals and used as they are, or then being re-dissolved to form a thin film as a component layer in a solar cell device. The trap density in single crystals varies, among the lowest reported being 2∙10 11 cm -3 and most of the deep trap states are located at crystal surfaces.
To improve the performance of the solar cell it is important to reduce the trap states as much as possible to avoid charge recombination, which lowers the efficiency. In this talk, an approach to improve crystal quality will be presented, specifically described from observations at the nanoscale. The presentation will cover the material formation procedure, characterization and photovoltaic performance.
"My research interests are on synthesis and characterization of new solar cell materials. I investigate structural, optical and electronic properties by combining different experimental techniques. The more understanding of the material will open up the opportunity to tailor the functionalities both in small scale and as a solar cell system. An important part of the research is the design of hybrid organic/inorganic solar cells with both specific microstructures and as thin film
devices." - Dr Malin Johansson
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