The Perovskite-Info newsletter (February 1, 2022)

A research group at FAU and the Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (HI ERN) have worked on a design aimed at significantly increasing the operational stability and life span of perovskite solar cells. Their design is based on a bilayer of polymers that protects the perovskites from corrosion at the same time as allowing uninterrupted charge transfer.

Until now, despite perovskite solar cells' potential, two major disadvantages have become apparent. Firstly, they do not have a particularly long life span, as perovskites tend to corrode on their interfaces and their performance capacity sinks rapidly, sometimes within days. Secondly, perovskite modules are not particularly robust in elevated temperatures, which severely limits their stability in practical use scenarios. This is mainly down to the layers doped with ions that are required for transporting the charge carriers but that can also lead to undesired secondary reactions.

An international team of researchers from EPFL, North Carolina State University, Centre for Hybrid and Organic Solar Energy (CHOSE) at the University of Rome Tor Vergata and Uppsala University has demonstrated a technique for producing perovskite photovoltaic materials on an industrial scale, which could reduce the cost and improve the performance of mass-produced perovskite solar cells. The technique is low-cost, simple and energy-efficient.

“In the lab, researchers produce perovskite photovoltaic materials using a technique called spin coating, which creates a thin film of perovskite on a substrate – but only on a small scale,” says Aram Amassian, co-corresponding author of a paper on the work and a professor of materials science and engineering at North Carolina State University.

Researchers from KAUST and the University of Bologna have examined the root causes of harmful top-contact delamination in p-i-n perovskite/silicon tandem solar cells. Their findings aim to improve the stability of tandem modules, and prompt a search for new interfacial linking strategies to enable mechanically strong perovskite-based solar cells, as required for commercialization.

In their work, by combining macroscopic and microscopic analyses, the team identified the interface between the fullerene electron transport layer and the tin oxide buffer layer at the origin of such delamination. Specifically, they found that the perovskite morphology and its roughness play a significant role in the microscopic adhesion of the top layers, as well as the film processing conditions, particularly the deposition temperature and the sputtering power.