Inorganic perovskite solar cells are almost ready for the market with record efficiency and stability
Scientists from Kaunas University of Technology (KTU), in collaboration with international partners, report one of the highest efficiencies to date for all-inorganic perovskite solar cells and, crucially, show that they can operate stably for hundreds of hours, closing the gap with commercial silicon. “Perovskite solar cells are one of the fastest growing solar technologies in the world – they can be lightweight, thin-film and flexible, and most importantly, they are made of low-cost materials,” says KTU researcher Dr. Kasparas Rakstys.
The team tackled perovskite instability by devising a passivation approach that forms a protective 2D layer on top of a 3D inorganic perovskite. They synthesized perfluorinated 2D ammonium cations whose highly electronegative fluorine atoms reduce the electron density of the ammonium group, allowing hydrogen bonding between the anchoring ammonium group and lead iodide fragments.
“Passivation makes the perovskite surface chemically inactive, eliminating defects introduced during production,” he noted. For fully inorganic compositions, adhesion is typically poor: “Simply put, 2D layers do not adhere to pure inorganic perovskite,” he said.
The new chemistry overcame that barrier: “The result was the formation of a stable 2D layer on the surface of the 3D inorganic perovskite. This time, the 2D layers finally bonded, forming robust heterostructures that remain stable even at high temperatures,” Dr. emphasized. Rakstys.
Devices exceeded 21 percent efficiency; mini modules with active areas more than 300 times larger than standard laboratory cells reached nearly 20 percent and worked stably for more than 950 hours at 85oC under continuous light.
“Although solar cells do not normally reach such high temperatures under real operating conditions, these standardized stability tests are used to assess their long-term durability, and such high stability is practically comparable to the requirements of commercial silicon cells,” he added.
The work, involving more than 20 researchers, appears in Nature Energy and underlines that next-generation perovskite technology is moving towards commercial application.
Research report:Cation interdiffusion control for 2D/3D heterostructure formation and stabilization in inorganic perovskite solar panels
