Novel solar cells: Perovskite solar cells: Quantum dot solar cells; Dye-sensitized solar cells
Global climate change and the ever-increasing energy demand forces humankind to replace conventional energy sources (fossil fuels) with renewable energy. Since solar energy has by far has the largest potential of renewable energy sources, it is evident that this resource needs to be exploited to a much larger extend than presently. Very large-scale implementation of solar energy is needed. The most convenient method to convert solar energy into useful energy is by means of photovoltaics. Photovoltaics (PV) or solar cells convert light directly into electricity. Due to the relative low power density of sunlight and its daily and annual variations, very large areas need to be covered with PV in order to make a serious global impact (thousands of square kilometers). The market-dominating silicon solar cells have some serious limitations: their production is energy intensive, due to the large amount of high purity silicon needed. Its production wafer-based and relatively slow.
There is therefore a strong need for new PV technologies that (1) are as efficient or more efficient than silicon-based solar cells, (2) require much less energy and materials in production, and (3) can be produced at a high speed with low-cost methods.
To develop new, efficient solar cell technologies that have better performance and a lower environmental impact than existing technologies. Performance under both outdoor and indoor conditions (with much lower light intensities) is of importance. Long-term stability is a critical factor for new technologies.
We also look into tandem solar cells, where solar cells with different absorption characteristics are stacked to increase the overall solar cell efficiency.
We are mainly using solution-based deposition processes for our solar cells, such as spin-coating, screen printing and slot-die coating. Slot-die coating is suited as a high-throughput deposition technique in industry. Ultimately, this process is low in cost and energy efficient compared to vacuum techniques.
A wide variety of techniques is used to study our solar cells and its components. Transient opto-electrical techniques give insight in charge separation and recombination in the solar cell. In stability tests, the solar cell performance is monitored in time under conditions of high temperature or high light intensity. Changes on the atomic scale can be found using advanced beam-line techniques.
Perovskite solar cells give efficiencies of more than 20% in our lab. These cells absorb light up to 800 nm. They are combined in tandem solar cells with CIGS solar cells and quantum dot solar cells, which can absorb up to 1200 nm.
Gerrit Boschloo, Dept. Chemistry –Ångström Laboratory, Physical Chemistry
Erik Johansson, Dept. Chemistry –Ångström Laboratory, Physical Chemistry
Other funding agencies
Swedish Energy Agency
Swedish Science Foundation (VR)
Swedish Foundation for Strategic Research (SSF)
Olle Engkvists Stiftelse