Decreasing halide segregation in wide-bandgap mixed-halide perovskite photo voltaic cells utilizing redox mediators – Insta News Hub

Multi-junction photo voltaic cells, photo voltaic cells comprised of many particular person semiconductor junctions stacked collectively, have the potential of outperforming single-junction photo voltaic cells each by way of effectivity and stability. In recent times, materials scientists and engineers have been making an attempt to determine viable materials mixtures for fabricating these photo voltaic cells.

A category of supplies discovered to be promising for these functions is metal halide perovskites, semiconductors with inherent properties which are advantageous for creating numerous optoelectronic units and photovoltaics. Whereas the effectivity of tandem photo voltaic cells based mostly on these semiconductors has step by step improved and not too long ago reached 24%, their stability is hindered by the extreme section segregation of mixed-halide perovskites.

Researchers at Metropolis College of Hong Kong not too long ago got down to handle this limitation of mixed-halide perovskite photo voltaic cells. Their paper, published in Nature Power, introduces a method that might enhance the long-term stability and photovoltage of those photo voltaic cells, using newly designed redox mediators based mostly on anthraquinone compounds.

“Halide segregation critically limits the soundness of mixed-halide perovskite photo voltaic cells underneath system operational situations,” Shengfan Wu, Yichao Yan and their colleagues wrote of their paper. “There’s a sturdy indication that halide oxidation is the first driving pressure behind halide de-mixing. To alleviate this drawback, we develop a sequence of multifunctional redox mediators based mostly on anthraquinone that selectively scale back iodine and oxidize metallic Pb⁰, whereas concurrently passivating defects by tailor-made cationic substitution.”

The brand new anthraquinone-based redox mediators designed by Wu, Yan and their colleagues selectively scale back iodine whereas oxidizing metallic Pb⁰. Notably, the oxidation of halides with a comparatively low oxidation potential in the end allows the transport of halide mass, in flip resulting in the section segregation noticed in perovskites.

The anthraquinone-derived redox mediators designed by the researchers, particularly AQSH, AQSN and AQSP, can in the end suppress halide segregation in perovskites. This may translate to a better stability of photo voltaic cells based mostly on mixed-halide perovskites.

To guage their proposed design technique, the researchers used it to develop single-junction wide-bandgap perovskite photo voltaic cells. These cells have been discovered to realize a power-conversion effectivity of 19.58% and a excessive open-circuit voltage of 1.35 V for 1.81-eV PSCs, whereas additionally exhibiting enhanced stability.

“The system retains 95% of its preliminary effectivity after working at its most energy level for 500 h,” wrote the researchers. “Most notably, by integrating the perovskite system into the monolithic perovskite-organic tandem photo voltaic cell as a wide-bandgap subcell, we report an effectivity of 25.22% (licensed 24.27%) with spectacular long-term operational stability (T₉₀ > 500 h).”

The brand new redox mediator-based design technique proposed by this staff of researchers may quickly assist to reinforce the efficiency of different mixed-halide perovskite natural tandem photo voltaic cells with various compositions. This might in the end facilitate the large-scale deployment of those photo voltaic cells, contributing to ongoing efforts aimed toward decarbonizing electrical energy technology.

“Each the spectacular effectivity and operational stability achieved by our tandem cells reveal the substantial potential of perovskite organic-tandem photo voltaic cells to outperform state-of-the-art perovskite-based tandem solar cells,” the researchers concluded.

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