Perovskite solar cells have high efficiency, but it can be further increased.
Specialists at the Laboratory of New Materials for Solar Energy at the Faculty of Materials Science of Moscow State University investigated in detail the interaction of hybrid perovskites with focused laser radiation. The result was the development of an improved method for assembling perovskite solar cells using laser cutting.
Hybrid halide perovskites form a new class of semiconductor materials. Using them as a light-absorbing material in perovskite solar cells, it is possible to obtain an efficiency of more than 25%, which is better than the record values for the most common solar cells made of polycrystalline silicon.
To form a large area solar cell, a large sheet is usually cut into strips, which are then connected in series. This allows you to increase the voltage and efficiency of the resulting module. However, the simultaneous increase in the area of “dead zones” – areas in compounds that are not involved in the generation — prevents the panel from increasing efficiency. To reduce the size of the dead zones, it is necessary to improve the technology of laser cutting of materials used in the solar cell.
The difficulty lies in the fact that a perovskite solar cell consists of several layers, and only some of them need to be cut so that the others are not damaged, in particular, due to a cascade of thermochemical and photochemical reactions with the release of gaseous decomposition products that make it difficult to control the cutting parameters.
The researchers studied these reactions by Raman spectroscopy and determined the main decay products of perovskite under the influence of high-power laser radiation. In addition, they found that volatile decomposition products condense on the surface of perovskite films, increasing the size of the dead zones.
The proposed method for minimizing undesirable processes is to feed a directed inert gas stream into the cutting region.