Novel green solvent could help scale up fabrication of perovskite-based tandem solar cells

Lately, engineers have been attempting to develop different photovoltaic (PV) applied sciences that may very well be extra reasonably priced and scalable than silicon-based photo voltaic cells, whereas additionally exhibiting good power-conversion efficiencies and retaining these efficiencies over time.

These rising PVs embrace perovskite-based tandem solar cellsthat are made up of two layers (i.e., sub-cells) with complementary light-absorption properties stacked on prime of one another.

Whereas these photo voltaic cells obtain promising power-conversion efficiencies, to be deployed on a large-scale, with out harming the atmosphere, these cells might want to comprise environmentally pleasant solvents. Notably, most inexperienced solvents created to this point are ineffective when utilized to wide-bandgap perovskites, thus the fabrication of tandem photo voltaic cells utilizing these supplies to this point relied on poisonous solvents primarily based on N,N-dimethylformamide (C₃H₇NO).

Researchers at Nanjing College and different institutes have created a brand new inexperienced solvent that may successfully dissolve cesium and bromide salts in perovskites and will thus be well-suited for the fabrication of each wide-gap and narrow-gap perovskite-based tandem photo voltaic cells. This solvent, introduced in a paper published in Nature Poweraccommodates dimethyl sulfoxide, acetonitrile and ethyl alcohol.

“In earlier analysis, our workforce had reached a high performance of 24.5% in all-perovskite tandem modules, which reveals an enormous potential for commercialization,” Ke Xiao, co-author of the paper, instructed Tech Xplore.

“Considering that the environmental and health safety during the fabrication process remains the most important issue for future scalable mass production, the toxic volatile nature of conventional perovskite solvents determines that they are difficult to manage in industrial production.”

The primary goal of this research by Xiao and his colleagues was to determine a comparatively secure and non-toxic solvent system that might scale back poisonous waste ensuing from the manufacturing of perovskite-based photo voltaic cells.

The solvent they created consists of dimethyl sulfoxide and acetonitrile, two chemical compounds that may dissolve cesium and bromide salts, together with ethyl alcohol, which prevents the degradation of the chemical compounds initiating chemical reactions in perovskites.

“In our recent workwe used the nitrogen gas blowing assisted blade-coating method to prepare large-area wide-bandgap perovskite films,” defined Xiao.

“The most notable achievement of this new work is the proposal of a green solvent system that is suitable for scalable fabrication for wide-bandgap perovskites. This solvent system is compatible not only with different wide-bandgap perovskites, but also with narrow-band gap perovskites, which means that this solvent system can be widely applied in various types of tandem cells in the future.”

The researchers used the inexperienced solvent they developed to manufacture blade-coated wide-bandgap perovskite photo voltaic cells. In preliminary assessments, these photo voltaic cells carried out properly, attaining energy conversion efficiencies of 19.6% (1.78 eV) and 21.5% (1.68 eV).

They then used these cells to create 20.25 cm² all-perovskite tandem photo voltaic modules that achieved a better power-conversion effectivity of 23.8%. Sooner or later, the brand new solvent may very well be additional examined and used to manufacture different photo voltaic modules, doubtlessly contributing to the environmentally-friendly and large-scale fabrication of tandem photo voltaic cells primarily based on perovskites.

“In our next studies, we plan to continue trying to reduce costs and improve the efficiency of all-perovskite tandem modules, as this is essential for industrialization,” added Xiao. “Now that we (have) identified the green solvent system, the next step will be to achieve larger-area fabrication in ambient air to avoid using redundant glove box.”

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