A new kind of photo voltaic technological know-how has appeared promising in recent many years. Halide perovskite solar cells are equally significant-accomplishing and low-charge for creating electrical energy – two vital substances for any successful photo voltaic technological know-how of the foreseeable future. But new photo voltaic cell components need to also match the balance of silicon-centered solar cells, which boast far more than 25 several years of trustworthiness.
In recently published exploration, a crew led by Juan-Pablo Correa-Baena, assistant professor in the College of Components Sciences and Engineering at Ga Tech, shows that halide perovskite solar cells are a lot less steady than formerly considered. Their get the job done reveals the thermal instability that occurs inside of the cells’ interface layers, but also gives a path forward towards reliability and efficiency for halide perovskite solar technology. Their exploration, revealed as the go over tale for the journal Highly developed Components in December 2022, has fast implications for both equally academics and business specialists functioning with perovskites in photovoltaics, a area concerned with electric currents created by daylight.
Direct halide perovskite photo voltaic cells promise top-quality conversion of sunlight into electrical electrical power. Now, the most frequent method for coaxing high conversion performance out of these cells is to handle their surfaces with significant positively charged ions recognised as cations.
These cations are too significant to match into the perovskite atomic-scale lattice, and, upon landing on the perovskite crystal, modify the material’s framework at the interface exactly where they are deposited. The resulting atomic-scale problems limit the efficacy of existing extraction from the solar cell. In spite of awareness of these structural alterations, exploration on no matter if the cations are secure following deposition is restricted, leaving a gap in comprehension of a process that could affect the long-expression viability of halide perovskite photo voltaic cells.
“Our concern was that throughout extensive periods of photo voltaic mobile operation the reconstruction of the interfaces would go on,” said Correa-Baena. “So, we sought to understand and display how this method happens about time.”
To have out the experiment, the team designed a sample solar system working with regular perovskite movies. The machine features eight independent solar cells, which enables the researchers to experiment and make details based mostly on each and every cell’s overall performance. They investigated how the cells would execute, equally with and with no the cation area cure, and researched the cation-modified interfaces of each and every cell right before and immediately after prolonged thermal strain working with synchrotron-based mostly X-ray characterization strategies.
Initial, the scientists exposed the pre-treated samples to 100 degrees
“Our work revealed that there is concerning instability introduced by treatment with certain cations,” said Carlo Perini, a research scientist in Correa-Baena’s lab and the first author of the paper. “But the good news is that, with proper engineering of the interface layer, we will see enhanced stability of this technology in the future.”
The researchers learned that the surfaces of metal halide perovskite films treated with organic cations keep evolving in structure and composition under thermal stress. They saw that the resulting atomic-scale changes at the interface can cause a meaningful loss in power conversion efficiency in solar cells. In addition, they found that the speed of these changes depends on the type of cations used, suggesting that stable interfaces might be within reach with adequate engineering of the molecules.
“We hope this work will compel researchers to test these interfaces at high temperatures and seek solutions to the problem of instability,” Correa-Baena said. “This work should point scientists in the right direction, to an area where they can focus in order to build more efficient and stable solar technologies.”
Reference: “Interface Reconstruction from Ruddlesden–Popper Structures Impacts Stability in Lead Halide Perovskite Solar Cells” by Carlo Andrea Riccardo Perini, Esteban Rojas-Gatjens, Magdalena Ravello, Andrés-Felipe Castro-Mendez, Juanita Hidalgo, Yu An, Sanggyun Kim, Barry Lai, Ruipeng Li, Carlos Silva-Acuña, Juan-Pablo Correa-Baena, 17 October 2022, Advanced Materials.