The Chinese Academy of Sciences (CAS) recently announced significant progress in the field of perovskite solar cells.
CAS.COM
The Chinese Academy of Sciences (CAS) recently announced significant progress in the field of perovskite solar cells. Researchers Ge Ziyi and Liu Chang from the Ningbo Institute of Materials Technology and Engineering, CAS, have successfully addressed the issue of iodide (I⁻) migration in perovskite solar cell devices, a key factor in enhancing their operational stability.
The team introduced 2,1,3-benzothiadiazole and 5,6-difluoro-4,7-dibromo derivatives into the perovskite precursor solution. Their findings revealed that the strong coordination interactions between the unhybridized p orbitals of these compounds and the lone pair electrons of iodide ions effectively inhibit the deprotonation of methylammonium iodide (MAI) and formamidinium iodide (FAI), as well as the subsequent conversion of I⁻ to I₂. Additionally, the highly electronegative fluorine atoms enhance electrostatic interactions with iodide ions. Together, these effects reduce perovskite decomposition and lower the density of iodine vacancy defects.
As a result, the team achieved a power conversion efficiency (PCE) exceeding 26% in inverted single-junction perovskite solar cells, paired with remarkable operational stability. Under the ISOS-L-3 testing protocol, the treated solar cells retained 85% of their initial PCE after 1,000 hours of aging. Moreover, when the BT2F-2B compounds were applied to wide-bandgap perovskite systems, all-perovskite tandem solar cells reached an impressive PCE of 27.8%, showcasing the versatility and effectiveness of this approach.This breakthrough marks a major advancement in the development of high-efficiency and durable perovskite solar cells, offering new opportunities for sustainable energy technologies.