The existing characterization procedures to evaluate emerging photovoltaic devices are not appropriate for halide perovskite solar cells, a new generation of solar cells called to overcome the present state-of-the-art technologies. A vast group of scientists with Prof. Pavel A. Troshin representing Skoltech has reached a consensus on the suitable procedures and the variables to be reported in stability studies of this kind of solar cells. The consensus statement, highlighted in the last issue of Nature Energy, updates the ISOS protocols for the stability assessment of perovskite photovoltaics with additional procedures to account for properties specific to this technology.
Perovskite solar cells (PSCs) represent a new kind of photovoltaic devices expected to rival the widespread silicon panels. The efficiency of perovskite-based solar cells is already superior, but their lifespan must be extended. This is the pending issue for the PSCs to reach commercialization. However, the existing qualification tests to evaluate the performance of solar cells are not appropriate for PSCs, as these have different material properties and device architectures. Therefore, publications studying the stability of PSCs lack consistency in the experimental procedures used and the parameters reported, which hampers data comparison and a proper understanding of the cell degradation mechanisms.
A large group of scientists decided to put an end to this situation: 59 leading researchers from 51 affiliations have agreed on how the stability of perovskite cells should be assessed and reported. The discussion was led by Prof. Mónica Lira-Cantú, Group Leader of the ICN2 Nanostructured Materials for Photovoltaic Energy Group, and by Prof. Eugene A. Katz, Professor at the Ben-Gurion University of the Negev, Israel. Among the authors are remarkable researchers such as Prof. Nam-Gyu Park and Prof. Henry J. Snaith, Nobel Prize candidates in 2017 for their discovery of the perovskite cells. Skoltech team was represented by Prof. Pavel Troshin. The result of the discussion is a consensus statement published in Nature Energy and highlighted in the journal editorial.
The experts have complemented the existing protocols with a set of testing procedures that account for specific features of PSCs, including light-dark-cycling, the study of cell behavior under electrical bias in the dark or intrinsic stability testing, among others. The researchers have also proposed a checklist for reporting results aimed at improving reproducibility.
However, there is still work to be done. A technical report is a next step to pave the way for standardization, which would be the last station in this journey from lab to industry. In the context of a society demanding green solutions for energy production, the efforts devoted to standardizing the study of perovskites facilitate the advance towards a new generation of enhanced solar cells.
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Journal
Nature Energy