Flatter Materials Improve Solar Cell Performance

Improving the efficiency of solar cells requires materials free from impurities and structural defects. Scientists across many disciplines at KAUST have shown that 2-D organic-inorganic hybrid materials feature far fewer defects than thicker 3-D versions.

Modern-day electronics rely on technologies that can develop almost perfect crystals of silicon; flawless to the atomic level. This is crucial because defects and impurities scatter electrons as they flow, which adversely affects the material's electronic properties.

But hybrid perovskites, an exciting class of electronic material, cannot be constructed using the epitaxial or layer methods developed for silicon. Instead, they are produced using solution-based processes. While this makes them cheaper than silicon, it also makes purity much harder to achieve as defect population and species are sensitive to the processing conditions.

Osman Bakr from the KAUST Solar Center together with colleagues from multiple divisions across KAUST and the University of Toronto, demonstrate that two-dimensional layers of perovskite material can achieve levels of purity much higher than is possible than in their 3-D counterpart. "Two-dimensional hybrid perovskites are a subgroup of the big hybrid perovskite family," explains Wei Peng, lead author and doctoral degree recipient from Bakr's lab. "They can be derived by inserting large organic cations in three-dimensional perovskite structures."

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