Ruddlesden-Popper (RP) two-dimensional (2D) halide perovskite (HP), with attractive structural and optoelectronic properties, has shown great potential in optoelectrical devices. However, the relatively wide bandgap (E_g) and stability, which cause inferior efficiency, prevent its feasibility from further applications. To tackle these issues, for the first time, a novel fluorine-containing piperidinium spacer, (3-HCF₂CF₂CH₂OCH₂-PPH⁺), abbreviated as (4FH-PPH⁺), has been designed for the stable and efficient n = 1 2D HPs. Its fluorophobicity can significantly enhance the noncovalent interactions between cations and [PbI₆]^4- octahedra. The observed E_g of the fluorinated (4FH-PPH)₂PbI₄ perovskite is found to be 2.22 eV, which is the lowest value among all fluorinated perovskites reported so far. Interestingly, this fluorinated film-based 2D perovskite photodetector (PD) exhibits the outstanding responsivity of 502 mA W^-1, photodetectivity of 5.73 × 10¹⁰ cm Hz^1/2 W^-1, and impressive response/recovery time of 42/46 ms under 450 nm at 20 V. To the best of our knowledge, it is found for the first time that the 2D HP, with the fluorinated short-chained segment included into the organic spacer, shows remarkable stability for up to 49 days. These results strongly demonstrate the potential of the 2D fluorinated short-chained (4FH-PPH)₂PbI₄ HP with a low E_g as a promising candidate for next-generation optoelectronic devices.

This paper delves into the polymorphism of 2-[3-(trifluoromethyl)anilino]benzoic acid, commonly referred to as flufenamic acid (FA), a pharmaceutical agent employed in treating inflammatory conditions. The central focus of the study is on a newly unearthed solvatomorphic structure of FA in methanol (FAM), and a thorough comparison is conducted with the commercially available standard structure. Employing a comprehensive approach, including X-ray crystallography, Hirshfeld surface analysis, density functional theory (DFT), molecular docking, and molecular dynamics (MD) simulations, the research aims to unravel the structural and functional implications of solvatomorphism. The X-ray crystal structure analysis brings to light notable differences between the standard FA and solvatomorphic FAM, showcasing variations in intermolecular interactions and crystal packing. Key features such as hydrogen bonding, pipi stacking, and C-Hpi interactions are identified as influential factors shaping the stability and conformation of the compounds. Hirshfeld surface analysis further quantifies the nature and contribution of intermolecular interactions, providing a comprehensive perspective on molecular stability. Density functional theory offers valuable electronic structure insights, highlighting disparities in frontier molecular orbitals between FA and FAM. Molecular docking studies against prostaglandin D2 11-ketoreductase explore potential drug interactions, unveiling distinct binding modes and hydrogen bonding patterns that shed light on how the solvatomorphic structure may impact drug-target interactions. In-depth molecular dynamics simulations over 100 ns investigate the stability of the protein-ligand complex, with root mean square deviation and root mean square fluctuation analyses revealing minimal deviations and affirming the stability of FAM within the active site of the target protein.