A simple solution prevents perovskite solar cells from degrading in the sun

Perovskite solar cells are emerging as one of the most promising high efficiency, low manufacturing cost photovoltaic technologies to make solar energy more accessible.

But one of its main disadvantages is that perovskite solar cells tend to degrade much faster in direct sunlight than their silicon counterparts, reducing their performance over time.

Now UCLA researchers have found a simple fabrication suitable for repair the cause of the degradationremoving the biggest barrier to commercialization and widespread adoption of the technology.

The usual surface treatment used to eliminate defects in solar cells consists of depositing a layer of organic ions which makes the surface too negatively charged.

The treatment aims to improve the efficiency of energy conversion during the manufacturing process of perovskite solar cells.

The UCLA-led team found that this treatment also unintentionally creates a more electron-rich surface, a potential trap for energy-carrying electrons to congregate on the surface. This, in turn, destabilizes the ordered arrangement of atoms, and over time perovskite solar cells become less and less efficient.

The UCLA team solved this problem by combining positively charged ions with negatively charged ions to treat the surface. The technique allows the surface to be more neutral and stable to electrons, while preserving the integrity of the defect prevention surface treatments.

The researchers tested their solar cells in the lab under accelerated aging conditions and 24/7 lighting designed to mimic sunlight. Solar cells treated with the new technique managed to retain 87% of their original performance converting sunlight into electricity for over 2,000 hours, far better than solar cells without the treatment, which reduced efficiency to 65%.

Our perovskite solar cells are among the most stable in terms of efficiency to date. At the same time, we have also established new fundamental knowledge, upon which the community can further develop and refine our versatile technique to design even more stable perovskite solar cells.

Shaun Tan, co-author of the study.

More information: www.nature.com (English text).

Via samueli.ucla.edu

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