US researchers build a 16% efficient mini perovskite solar panel that resists UV-induced degradation

July 10, 2024 Valerie Thompson

A US research team has fabricated a mini perovskite solar panel based on a special polymer hole transport layer material that reportedly improves the panel’s stability and efficiency.

“The stability of perovskite modules has not been shown to meet the 25-year service life requirement in many applications,” said the study’s corresponding author Jinsong Huang. pv magazinenoting that the group was able to build the panel after identifying an ultraviolet (UV) light-induced perovskite degradation mechanism as one of the main causes affecting the stability of the perovskite module.

“We report the degradation mechanisms of pin-structured perovskite solar cells under unfiltered sunlight and with LEDs,” the scientists explained, adding that they initially found the cause of UV light-induced degradation in outdoor testing to be in the weak chemical bond between the perovskite layer. the hole transporting materials (HTM) and the transparent conductive oxide layer (TCO) at the cell level. “This causes degradation of perovskite solar cells under sunlight with strong UV components.”

To mitigate the effects of this degradation, the scientists upgraded the perovskite solar cells used for the mini-modules with a hybrid HTM based on a combination of EtCz3EPA, a new molecule, and poly[bis(4-phenyl)-(246-trimethylphenyl)aminebathocuproine(PTAA:BCP)[bis(4-phenyl)-(246-trimethylphenyl)-aminebathocuproine(PTAA:BCP)[bis(4-fenyl)-(246-trimethylfenyl)aminebathocuproïne(PTAA:BCP)[bis(4-phenyl)-(246-trimethylphenyl)-aminebathocuproine(PTAA:BCP)

This combination reportedly resulted in a stronger bond layer at the interface of the perovskite and substrate when tested outdoors. “We improved the bonding in the perovskite/HTM/TCO region via a phosphonic acid group that bound to the TCO and via a nitrogen group that interacted with lead in perovskites,” the academics explained.

The cells were based on a substrate made of indium tin oxide (ITO), the new HTM, the perovskite absorber, a buckminsterfullerene (C60) electron transport layer, bathocuproin (BCP) and a copper (Cu) metal contact.

The 15 cm2 perovskite solar panel fabricated with this cell configuration was able to achieve an energy conversion efficiency of over 16% and maintain these efficiency levels for approximately 29 weeks of outdoor testing. The results were independently confirmed by the U.S. Department of Energy’s Perovskite PV Accelerator for Commercializing Technologies (PACT) accelerator.

“Real-world demonstration is a critical step toward commercialization, and we hope that by offering PACT these capabilities, researchers and companies can use this data to improve reliability,” the researchers said.

Their work is described in the article “Strongly adhesive hole transport layers reduce ultraviolet degradation of perovskite solar cells,” published in Science. The research team included members from the University of North Carolina, the Colorado School of Mines, the National Renewable Energy Laboratory (NREL), the University of Toledo and the University of California San Diego.

“This research is a true collaboration between organic synthetic chemists and solar cell device engineers working together to solve big problems. Furthermore, the chemistry to prepare the molecule of interest in this study is relatively simple and just the tip of the iceberg,” Alan Sellinger, a professor at the Colorado School of Mines, said in a press release. Looking at upcoming research projects, Huang said the group will “continue to understand the degradation mechanisms and find methods to overcome them.”