10.12.2018 aktualizacja 10.12.2018

Polish idea for efficient perovskites

Photo by D. Prochowicz Photo by D. Prochowicz

Photovoltaic cells based on perovskites are more efficient if perovskite is mechanically grounded instead of being obtained with the traditional method - in a solution. Dr. Daniel Prochowicz from the Institute of Physical Chemistry PAS is working on explaining this phenomenon.

Perovskites are high light absorption materials, which allow to convert solar energy into electricity in a photovoltaic cell. The cell is lightweight, because the perovskite layer can be extremely thin.

As a result, in the future, mobile chargers could have the form of a thin film, drawing energy from a light source. Thin and flexible photovoltaic modules will be applied to the roofs of cars and office windows, powering vehicles and supplying buildings with energy.

But before perovskite cells find practical applications, efficient ways of obtaining perovskites must be developed. Dr. Daniel Prochowicz from Prof. Janusz Lewiński`s team developed an efficient method for obtaining various hybrid inorganic-organic halide perovskites for photovoltaic applications.

According to Dr. Prochowicz, the photovoltaic market is dominated by silicon cells. Perovskite cells can achieve similar performance despite being much lighter. With halide perovskites, a very thin 400-500 nanometer layer can be obtained and used to cover a cell. This can translate into low production costs of perovskite solar modules.

Perovskites in the form of a thin film can be obtained in two ways. The standard method consists in dissolving the substrates in an organic solvent. The solution is spread to obtain a thin layer under the influence of centrifugal force or applied to the surface by means of a spray. It is then heated to crystallize the perovskite.

Scientists from the Institute of Physical Chemistry PAS used the mechanochemical method of synthesis to obtain a wide range of halide perovskites. They obtain perovskites by grinding and use such mechanoperovskites to build photovoltaic cells. To cover the cell, ground perovskite has to be dissolved, but the process is slightly different and cheaper. In addition, perovskites obtained by grinding can be stored for a long time in an inert gas atmosphere. They can be used at any point to build solar cells without worrying about the deterioration of parameters.

"Mechanochemistry allows to carry out chemical reactions without solvents and high temperatures. Substance synthesis is cheaper because of lower energy consumption. Without solvent there is little waste, and therefore it is an environmentally friendly method. The mechanochemical processes allow to obtain products faster, cleanly and with high efficiency" - explains Dr. Daniel Prochowicz.

The thin layer obtained by applying the solution containing the dissolved mechanoperovskite was more homogeneous. It had fewer structural defects and charges accumulating on the surface of the film than the perovskite layer obtained by a standard method.

"The solar cell based on perovskite materials obtained mechanochemically had better photovoltaic parameters than the cell containing an analogous perovskite obtained by the standard method" - says Dr. Prochowicz.

The researcher has already used mechanochemical processes to obtain metal complexes, coordination polymers and microporous materials. Recently, he developed this method in Prof. Michael Graetzel`s team at Ecole Polytechnique de Lausanne in Switzerland. He will continue his work in the Institute of Physical Chemistry PAS as part of the HOMING research project financed by the Foundation for Polish Science. The scientist was previously a stipend holder of the START programme, and in October this year he received the "Polityka" scientific prize for young researchers in the field of science.

PAP - Science in Poland, Karolina Duszczyk

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