000K utf8 1100 $c2025 1500 eng 2050 urn:nbn:de:gbv:8:3-2025-00275-8 2051 10.1038/s41598-024-78259-9 3000 Chowdhury, Subhadip 3010 Bharatiya, B 3010 Bhunia, Satyaban 3010 Giri, Rajendra Prasad 3010 Mukhopadhyay, Mrinmay K 3010 Murphy, Bridget 3010 Sanyal, Milan K 3010 Satpati, Biswarup 3010 Shen, Chen 4000 Investigation on the formation of two dimensional perovskite nanostructures at the water surface through self initiated reaction$hSpringer Science and Business Media LLC [Chowdhury, Subhadip] 4030 $nSpringer Science and Business Media LLC 4209 The emerging class of hybrid organic-inorganic perovskites (HOIPs) has exhibited fascinating properties for a wide range of technological applications. With halide ions, HOIPs have provided novel optoelectronic devices including efficient solar cells and with pseudohalide anions-like formate (HCOO-), enigmatic electromagnetic properties have been obtained in HOIPs. Large-scale synthesis of such 2D HOIP films is of immense importance for the advancement of its application as solar materials. We have shown using in-situ X-ray measurements that the Langmuir monolayer of perovskite can be formed at the air-water interface by spreading stearic acid molecules on the water subphase having (C4H9NH3)2PbBr4 molecules. The 2D lead formate perovskite films are formed at the air-water interface through a self-initiated reaction and the in-situ X-ray scattering and ex-situ Raman spectroscopy measurements revealed this reaction process. The spreading of lipid molecules having positive and negative head-group charges as surfactants over the water surface shows that the formation of perovskite nanofilms at the air-water interface specifically requires the presence of HCOO- head-group of stearic acid. In this room temperature interfacial reaction, formate anions come from the stearic acid monolayer present on the water surface and completely replace bromines in the perovskite present in water subphase to form (BA)2Pb(HCOO)4 at the air-water interface. Our results show an easy route for large-scale synthesis of 2D pseudohalide perovskites. 4950 https://doi.org/10.1038/s41598-024-78259-9$xR$3Volltext$534 4950 https://nbn-resolving.org/urn:nbn:de:gbv:8:3-2025-00275-8$xR$3Volltext$534 4961 https://macau.uni-kiel.de/receive/macau_mods_00005800 5051 530 5051 530 5550 2D Hybrid Organic-inorganic Perovskite 5550 Langmuir Monolayer 5550 Liquid Surface X-ray Scattering 5550 Surface-initiated Reaction 5550 White Light Photoluminescence