Plugging performance-sapping issues that hamper perovskite performance

• A multifunctional molecule that connects numerous atomic-scale defects in perovskite solar products can dramatically improve the longevity and electric result of this promising solar modern technology, KAUST scientists have revealed.

Perovskites are a different solar-cell material to silicon. They normally consist of a combination of negatively charged iodine or bromine ions as well as positively charged lead and organic ions. Changing the ion combination can create wide bandgap perovskites that capture the solar wavelengths that silicon does not successfully soak up. This suggests both materials could be integrated in tandem cells to record even more power from the Sun.

Nevertheless, perovskites inevitably feature issues, such as where a specific ion did not slot into area during manufacture, leaving a space in the structure. These reactive sites can add to quick efficiency decrease-- unless they can be connected. "Flaw passivation is really important for improving the lasting security of perovskite solar cells," states Furkan Isikgor, a researcher in Stefaan De Wolf's group.

Problem sites in perovskites can be positively or negatively charged depending on which ion is missing out on, but chemical ingredients for defect passivation can usually plug one type of issue or the various other. However a molecule called phenformin hydrochloride (PhenHCl) overcomes this trouble, Isikgor, De Wolf as well as their colleagues have actually shown.

"PhenHCl works extremely well owing to its multifunctional structure," Isikgor claims. The molecule contains an electro-positive ammonium head group that can plug adversely charged flaws as well as an electro-negative amine and also imine group body to plug positive gaps.

The researchers showed that PhenHCl increased the power conversion effectiveness (PCEs) of vast bandgap perovskites from 16.7 percent in without treatment cells up to 20.5 percent in cured cells. "Furthermore, PhenHCl passivation boosts the PCE of textured perovskite/silicon tandem solar cells from 25.4 percent to 27.4 percent," Isikgor claims.

PhenHCl passivation likewise dramatically enhanced the stability of the perovskite solar cell. "Under continual light soaking, the PhenHCl-passivated device maintained 80 percent of its post-burn-in effectiveness for around 106 hrs of procedure," Isikgor says. The unattended gadget maintained 80 percent of its post-burn-in efficiency for only 5 hrs.

"Our simple holistic defect-passivation technique has dramatically improved the semiconductor top quality of solution-processed perovskites," states De Wolf. "Passivating the various kinds of flaws that may be present in perovskites with a single molecule is extremely appealing for industry," he includes. The following step will certainly be to integrate PhenHCl passivation with scaled-up perovskite manufacturing. "Concurrently, we are working on more improvements in device efficiency as well as security with extensive exterior screening," De Wolf includes.