$$News and Reports$$

Feb. 04, 2020

Metal halide perovskite solar cells currently dominate photovoltaic research, due to recent improvements in power conversion efficiency (with an impressive lab record of 25.2%) and long-term device stability, as well as low-cost fabrication procedures compatible with industrial manufacturing. However, existing characterization procedures to evaluate emerging photovoltaic devices are not appropriate for halide perovskite solar cells. Researches from the J. Blaustein Institutes for Desert Research at BGU's Sede Boqer campus (Dr. Mark Khenkin, Professors Eugene Katz and Iris Visoly-Fisher) joined forces with leading scientists in the field to develop a consensus on the suitable procedures for assessing and reporting stability of perovskite photovoltaics. The consensus statement was recently published in Nature Energy (https://rdcu.be/b0DiV ) and highlighted in the Editorial (https://www.nature.com/articles/s41560-020-0552-6 ).

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As stated in the Editorial titled “Perovskites take steps to industrialization": “Until now, the perovskite community lacked cohesion and consistency in identifying key tests that could reveal failure modes specific to perovskite cells (PSC), which are both cause and consequence of the limited understanding of device degradation. More effort is needed to understand degradation mechanisms in the first instance. To address this challenge, Monica Lira-Cantu (from the Catalan Institute of nanoscience and Nanotechnology, ICN2) and Eugene Katz (both corresponding authors of the paper) brought together a wide number of researchers in the field from universities, research centres and companies to reach a consensus on how to test perovskite solar cells for stability and how to accurately report data.“

The paper reflects an agreement of 59 leading researchers from 51 affiliations about the ways in which the stability of perovskite cells should be assessed and reported. Inspired by a previous collaboration on organic photovoltaic cells, which in 2011 yielded recommendations for evaluating the stability of these devices (so-called 'ISOS protocols'), the scientific community devoted to PSCs set on a similar endeavour. Katz and Lira-Cantu initiated a round table discussing PSCs stability assessment at the 11th International Summit on Organic and Hybrid Photovoltaics Stability held in China in October 2018, posing the origin of the present consensus. The experts have complemented the existing ISOS protocols with a set of testing procedures that account for specific features of PSC stability and degradation issues. The researchers have also proposed a checklist for reporting results aimed at improving comparisons between data from different laboratories and from different device architectures, towards using machine learning and big-data analysis methods for studying large, standardized databases. The set of procedures and practices suggested in the paper should serve as an intermediate stage in PSC technology maturation, aimed at the identification of degradation pathways and the prospects for their mitigation. However, there is still work to be done to pave the way for standardization of the PSC lifetime predictions, which would be the last station in this journey from lab to industry.

Article reference:

Mark V. Khenkin, Eugene A. Katz, et. al., Mónica Lira-Cantú. Consensus Statement for Stability Assessment and Reporting for Perovskite Photovoltaics based on ISOS Procedures. Nature Energy, 5, p. 35–49 (2020).

http://dx.doi.org/10.1038/s41560-019-0529-5