The Perovskite-Info newsletter (November 2, 2021)

A research team from the Fraunhofer Institute for Solar Energy Systems, NREL, Solaronix SA and the Materials Research Center of the University of Freiburg has reported perovskite solar cells with carbon-based electrodes, which demonstrate impressive resilience against reverse-bias-induced degradation.

Previous studies have shown that a negative voltage applied to conventional perovskite solar cell stacks resulted in breakdown and irreversible destruction of the device. In this study, the international research team identified two main degradation mechanisms. The first is iodine loss due to hole tunneling into perovskite, which takes place even at low reverse-bias but decomposes the perovskite only after long time durations. Another factor is local heating at large reverse-bias leading to the formation of PbI₂, which starts at shunts and then follows the path of the least resistance for the cell current, which is primarily influenced by the electrode sheet resistance. The newly designed modules successfully endured the hotspot test conditions specified in IEC 61215-2:2016 international standard at an accredited module testing laboratory.

A research team at KTH Royal Institute of Technology has developed a synthetic alloy that increases perovskite cells’ durability while preserving energy conversion performance.

“Perovskite usually dissolves immediately on contact with water,” says co-author James Gardner, a researcher at KTH. “We have proven that our alloyed perovskite can survive for several minutes completely immersed in water, which is over a 100 times more stable than the perovskite alone. What’s more, the solar cells that we have built from the material retain their efficiency for more than 100 days after they are manufactured.”

A collaborative research team that included scientists from the University of Queensland (UO), the University of Leeds, Université Paris-Saclay and University of Cambridge, has developed perovskite-based composite glass that is virtually unbreakable and delivers crystal clear image quality.

UQ's Dr. Jingwei Hou said the discovery was a huge step forward in perovskite nanocrystal technology as previously, researchers were only able to produce this technology in the atmosphere of a laboratory setting as lead-halide perovskites NCs are extremely sensitive to light, heat, air and water. However, Hou said that “Our team of chemical engineers and material scientists has developed a process to wrap or bind the nanocrystals in porous glass. This process is key to stabilizing the materials, enhancing its efficiency and inhibits the toxic lead ions from leaching out from the materials.”

Scientists at the National Renewable Energy Laboratory (NREL) and Northern Illinois University (NIU) have developed a way to prevent lead from escaping damaged perovskite solar cells. This could go a long way in addressing concerns about potential lead toxicity.

Image by NREL, from Phys.org

The light-absorbing layer in perovskite solar cells contains a small amount of lead. Simply encapsulating solar cells does not stop lead from leaking if the device is damaged. Instead, chemical absorption may hold the key. The researchers report being able to capture more than 99.9% of the leakage.

Solliance recently announced that a collaboration with the M2N group of René Janssen at University of Technology Eindhoven has resulted in two world-records for 4T perovskite tandems.

The partners reported that they further optimized the wide-bandgap (1.69eV) perovskite cells with high near-infrared transparency for 4T tandem applications. The perovskite cell has reached a stabilized efficiency of 17.8% during 5-min maximum-power-point tracking. In combination with the Panasonic silicon bottom cell, a new world-record 4T perovskite/Si tandem efficiency of 29.2% was realized.