Shaping Tin Nanocomposites through Transient Local Conversion Reactions

Shape-preserving conversion offers a promising strategy to transform self-assembled structures into advanced functional components with customizable composition and shape. Specifically, the assembly of barium carbonate nanocrystals amorphous silica nanocomposites (BaCO3/SiO2) plethora programmable three-dimensional (3D) microscopic geometries, can subsequently be converted chemical compositions, while preserving original 3D geometry. Despite this progress, scope these reactions has been limited by requirement form salts. Here, we overcome limitation using single-step cation/anion exchange that is driven temporal pH change at converting nanocomposite. We demonstrate proof principle BaCO3/SiO2 tin-containing nanocomposites, metal without stable carbonate. find convert in single step hydroromarchite (Sn3(OH)2O2/SiO2) excellent preservation geometry fine features. explore versatility tunability Sn3(OH)2O2/SiO2 as precursor for compositions developing shape-preserving routes two desirable compositions: tin perovskites (CH3NH3SnX3, X = I or Br) tunable photoluminescence (PL) cassiterite (SnO2)—a widely used transparent conductor. Ultimately, findings may enable integration morphologies next-generation optoelectronic devices.