Polydopamine is a biomimetic self-adherent polymer, which can be easily deposited on a wide variety of materials. Despite the rapidly increasing interest in polydopamine-based coatings, the polymerization mechanism and the key intermediate species formed during the deposition process are still controversial. Herein, we report a systematic investigation of polydopamine formation on halloysite nanotubes; the negative charge and high surface area of halloysite nanotubes favour the capture of intermediates that are involved in polydopamine formation and decelerate the kinetics of the process, to unravel the various polymerization steps. Data from X-ray photoelectron and solid-state nuclear magnetic resonance spectroscopies demonstrate that in the initial stage of polydopamine deposition, oxidative coupling reaction of the dopaminechrome molecules is the main reaction pathway that leads to formation of polycatecholamine oligomers as an intermediate and the post cyclization of the linear oligomers occurs subsequently. Furthermore, TRIS molecules are incorporated into the initially formed oligomers.

Oxidative chemical vapor deposition (oCVD) is an extremely effective method for solvent-free deposition of highly conductive polypyrrole films, where polymer synthesis, doping, and film formation are combined in a single step.

Lead halide perovskite nanocrystals are highly attractive for next‐generation optoelectronics because they are easy to synthesize and offer great compositional and morphological tunability. However, the replacement of lead by tin for sustainability reasons is hampered by the unstable nature of Sn²⁺ oxidation state and by an insufficient understanding of the chemical processes involved in the synthesis. Here, an optimized synthetic route is demonstrated to obtain stable, tunable, and monodisperse CsSnI₃ nanocrystals, exhibiting well‐defined excitonic peaks. Similar to lead halide perovskites, these nanocrystals are prepared by combining a precursor mixture of SnI₂, oleylamine, and oleic acid, with a Cs‐oleate precursor. Among the products, nanocrystals with 10 nm lateral size in the γ‐orthorhombic phase prove to be the most stable. To achieve such stability, an excess of precursor SnI₂ as well as substoichiometric Sn:ligand ratios are key. Structural, compositional, and optical investigations complemented by first‐principle density functional theory calculations confirm that nanocrystal nucleation and growth follow the formation of (R‐NH₃⁺)₂SnI₄ nanosheets, with R = C₁₈H₃₅. Under specific synthetic conditions, stable mixtures of 3D nanocrystals CsSnI₃ and 2D nanosheets (Ruddlesden–Popper (R‐NH₃⁺)₂Cs_n−1Sn_nI_3n+1 with n > 1) are obtained. These results set a path to exploiting the high potential of Sn halide perovskite nanocrystals for opto‐electronic applications.