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Triple cation, mixed halide perovskite compositions have been reported to be more thermally stable, exhibit fewer phase impurities, and show higher power conversion efficiency and better reproducibility than single cation perovskites. In this work, we explain the formation of Cs0.05FA0.81MA0.14Pb(I0.85Br0.15)3via a multimodal in situ study combining structural information from synchrotron grazing-incidence wide-angle X-ray scattering (GIWAXS) and optical properties from photoluminescence (PL) spectroscopy with density functional theory calculations (DFT). The focus here is on the effects of the solvent and antisolvent during crystallization. The predominantly used solvents N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and the antisolvent chlorobenzene (CB) as well as the solvent–antisolvent–precursor interactions are investigated. Given the high elemental complexity and mutual interdependencies between solvent, antisolvent, and perovskite precursors, we found significant differences in the crystallization pathways. DMF-pure precursors show the formation of the DMF-containing intermediate phase and the nucleation of compositionally distinct perovskite phases, while when DMSO is added, only crystalline α- and δ-phases were found. In addition, the presence of DMSO helps the formation of α-perovskite. Coordination energy and bond order (BO) calculations support our experimental findings. Dripping of CB induces nucleation at room temperature, slows the α-phase formation rate, and appears to reduce the nucleation radius. These findings provide novel insights into solvent, antisolvent, and perovskite precursor interactions and their formation pathways. The complexity of interactions between solvents and reagents highlights the importance of understanding these effects to further improve the reproducibility and optimize processing conditions.

In this work, we report the condensation and stabilization of water vapors into water-repellent, methyl-functionalized, mesoporous, silica-based films at room temperature and atmospheric pressure using a soft alcohol-assisted method. The capillary pore fillings due to water adsorption were ensured by a fine control of partial vapor pressures of alcohol and water. A synergic coadsorption of alcohol and water was observed due to a reversible surface energy switching from hydrophobic to hydrophilic induced by the preferential interaction of the alkyl side of the surfactant alcohol molecules with the hydrophobic walls. The influences of the film mesoprosity as well as the type of the alcoholic coadsorbate (methanol, ethanol, and 1-propanol) were investigated, revealing various Kelvin’s law-like adsorption behaviors, depending on the alcohol carbon chain length. Interestingly, the stabilization of condensed domains of quasi-pure water phases was obtained in confined hydrophobic spaces by a presumed selective alcohol desorption. It was demonstrated that a small quantity of remaining Si–OH groups at the pore surface was sufficient to stabilize water nanodomains in hydrophobic pores. These results were based on in situ ellipsometric investigations, that further allowed measuring the wetting angle of water droplets trapped within the porous network, from which we could evaluate the quantity of polar −OH groups remaining in the methyl-functionalized, mesoporous, silica-based films. This first insight in alcohol/water coadsorption may open the door toward new generation of alcohol sensors.

In this work, unique functional devices exhibiting controlled gradients of properties are fabricated by dip-coating process in acceleration mode. Through this new approach, thin films with “on-demand” thickness graded profiles at the submillimeter scale are prepared in an easy and versatile way, compatible for large-scale production. The technique is adapted to several relevant materials, including sol–gel dense and mesoporous metal oxides, block copolymers, metal–organic framework colloids, and commercial photoresists. In the first part of the Article, an investigation on the effect of the dip coating speed variation on the thickness profiles is reported together with the critical roles played by the evaporation rate and by the viscosity on the fluid draining-induced film formation. In the second part, dip-coating in acceleration mode is used to induce controlled variation of functionalities by playing on structural, chemical, or dimensional variations in nano- and microsystems. In order to demonstrate the full potentiality and versatility of the technique, original graded functional devices are made including optical interferometry mirrors with bidirectional gradients, one-dimensional photonic crystals with a stop-band gradient, graded microfluidic channels, and wetting gradient to induce droplet motion.