In‐liquid Superspreading Space‐confined Epitaxy on Superamphiphilic Surfaces for Pt(II) Complex Crystalline Film Growth

Abstract Solution‐based method is regarded as a promising approach to fabricate large‐area, high‐quality crystalline films, owing to its low‐cost manufacturing and facile features. However, traditional solution‐based methods still suffer from random simultaneous nucleation and uncontrollable crystal growth which result in polycrystalline films and coffee‐ring effect. Herein, it is proposed that an in‐liquid superspreading space‐confined epitaxy approach on a superamphiphilic surface to fabricate crystalline films with controllable initial nucleation and crystal morphology. With delicate control of the liquid environment, concentration, and superspreading space‐confined solvent film thickness, planar crystalline films with high crystallinity and smooth morphology are obtained. A controllable dewetting crystallization mechanism is proposed, indicating that the diffusion coefficient, regulated by liquid environment, can control the dewetting process during crystallization. With the balance of solvent diffusion and solute precipitation in crystallization, the ordered in‐plane and out‐of‐plane molecular stacking is achieved. And the as‐prepared planar Pt(II) complex crystalline film exhibits multi‐signal sensing ability, which can be further used to fabricate the reaffirmed sensing detector for precise gas sensing in complex and unstable conditions. This study demonstrates a facile approach for crystalline film fabrication with controllable nucleation and morphology in a liquid environment, which holds promising applications in the construction of oxygen or water‐sensitive organic/inorganic devices.