New research by CHEOPS has found a way to reduce the ‘dead area’ or photovoltaic cells by applying an enhanced laser patterning process. This new development means that more of the area of a cell can be used for energy conversion, making it more efficient.
CHEOPS is a European research project started in February 2016, with a focus on upscaling perovskite photovoltaic cells, to provide low cost and efficient solar panels for the commercial market. It is co-funded by the European Union’s Horizon 2020 framework program which supports research and innovation throughout the continent.
CHEOPS is a conglomerate of twelve research teams from industries and prestigious universities, committed to finding and developing more efficient ways the technology can be applied outside of the lab. The project is coordinated by CSEM, Swiss Center for Electronics and Microtechnology. The private applied research and development center specializes (amongst other things) in photovoltaics (PV) research.
Perovskite photovoltaics are a synthetic compound, which share their crystalline structure with the naturally occurring mineral of the same name. Using the material to make solar cells promises to be very efficient with a low cost, however, very few attempts have been made to upscale the technology for commercial use. Previous efforts have reduced efficiencies from 20% to 9% and have caused many to question the viability of the technology outside of the lab.
Currently, to achieve suitable currents, photovoltaic cells must be split into a series of interconnected segments. It is these breaks in the material that need to be made as small as possible to be able to optimize the cell for energy conversion. This so-called ‘dead area’ has been reduced to a width of 400μm by using a new laser patterning process.
The process requires three lines of varying depth to create trenches in the cells, allowing the current to flow between the front contact and the electrode material attached to the back of the perovskite only. To do this, CHEOPS used three different laser sources. UV, IR and green lasers with varying pulse frequencies were used to remove create the trenches. The difficulty of this process lay in removing the unwanted layers without damaging the rest. In addition to this, the trenches had to balance being small enough to reduce the dead area while also being large enough for sufficient insulation.
Despite the challenges, CHEOPS produced a solar cell of 140mm2, which achieved an efficiency of 16% while decreasing the dead area to aperture area ratio to 8%. While this a remarkable achievement, CHEOPS has vowed to improve the laser patterning process further to reduce this ratio to 3-5%.
The project will conclude in 2019. CHEOPS aims to demonstrate a semi-transparent perovskite module with a 10% stabilized aperture area efficiency on a 20 x 30 cm. This new process is one small step to achieving this goal.
This story is reprinted from material from the official CHEOPS website, with editorial changes made by Azo Network. The original article can be found here.