In-situ surface reconstruction of CsPbl3 perovskite for efficient and stable solar cells.

[Display omitted] • Utilizing siloxane surfactants enable the top surface reconstruction of CsPbI 3. • A self-assembled siloxane ligand layer is formed on the surface of CsPbI 3. • The phase transition of CsPbI 3 can be efficiently suppressed. • The surface and interfacial defects in the perovskite are well passivated. • A champion efficiency of 21.42 % is achieved for CsPbI 3 solar cell. All-inorganic perovskite is a promising candidate for solar cell applications. However, a significant challenge lies in its poor phase stability to environmental moisture. To address this problem, we develop a strategy for in-situ reconstruction of the CsPbI 3 surface using siloxane surfactants such as 3-aminopropyltriethoxysilane (APTES) and 3-aminopropyltrimethoxysilane (APTMS), which both demonstrate multifunctional roles in surface engineering. The siloxanes undergo air-induced hydrolysis, leading to the formation of Si-O-Si networks. Additionally, the –NH 2 convert to –NH 3 +, enabling interaction with the I− ions on the surface of CsPbI 3. This facilitates the formation of a self-assembled siloxane cross-linked ligand layer, which offers extra function for providing water and oxygen shielding, consequently stabilizing the surface of CsPbI 3. Furthermore, the siloxane surfactants can passivate uncoordinated Pb2+ ions, resulting in a reduction of non-radiative recombination at the interface, thereby significantly augmenting device performance and stability. Following research comparisons, APTES with longer alkyl chains displays superior performance. As a result, with the APTES passivation, the PCE is increased from 19.01 % to 21.42 %, which is one of the highest PCE devices in pure CsPbI 3 PSCs reported so far. Meanwhile, the devices treated with APTES show superior moisture stability over those without APTES, especially in the absence of encapsulation. [ABSTRACT FROM AUTHOR]