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Phoenix666 [soylentnews.org] writes:

Perovskites, substances that perfectly absorb light, are the future of solar energy. Now, a rapid and environmentally safe method of production has been developed by chemists from Warsaw, Poland. Perovskites can now be synthesized by solid-state mechanochemical processes by grinding powders [phys.org], rather than in solutions at a high temperature.

We tend to associate the milling of chemicals with old-fashioned pharmacies and the pestle and mortar. It's time to change this—recent research findings show that by the use of mechanical force, effective chemical transformations take place in solid state substances. Mechanochemical reactions have been under investigation for many years by the teams of Prof. Janusz Lewiński from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) and the Faculty of Chemistry of Warsaw University of Technology. In their latest publication, the Warsaw researchers describe a surprisingly simple and effective method of obtaining perovskites - futuristic photovoltaic materials with a spatially complex crystal structure.

"With the aid of mechanochemistry we are able to synthesize a variety of hybrid inorganic-organic functional materials with a potentially great significance for the energy sector. Our youngest 'offspring' are high quality perovskites. These compounds can be used to produce thin light-sensitive layers for high efficiency solar cells," says Prof. Lewiński.

Perovskites are a large group of materials, characterized by a defined spatial crystalline structure. In nature, the perovskite naturally occurring as a mineral is calcium titanium(IV) oxide CaTiO3. Here, the calcium atoms are arranged in the corners of the cube. In the middle of each wall, there is an oxygen atom and at the centre of the cube lies a titanium atom. In other types of perovskite, the same crystalline structure can be constructed of various organic and inorganic compounds, which means titanium can be replaced by, for example, lead, tin or germanium. As a result, the properties of the perovskite can be adjusted so as to best fit the specific application—for example, in photovoltaics or catalysis, but also in the construction of superconducting electromagnets, high voltage transformers, magnetic refrigerators, magnetic field sensors, or RAM memories.
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"Two powders are poured into the ball mill: a white one, methylammonium iodide CH3NH3I, and a yellow one, lead iodide PbI2. After several minutes of milling, no trace is left of the substrates. Inside the mill, there is only a homogeneous black powder: the perovskite CH3NH3PbI3," explains doctoral student Anna Maria Cieślak.

The Perovskites created through mechanical assembly performed 10% better than those created using traditional solvents.

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