Gas sensors based on organic semiconductor materials (OSCs) have garnered significant attention due to their cost-effectiveness and ability to operate efficiently at room temperature. However, the performance of these sensors is often constrained by the grain boundaries and defects inherent in polycrystalline films typically produced by conventional methods. In this study, a novel approach was developed for fabricating large-area porous organic single-crystal films. Hydrophobic lattice structures were engineered on hydrophilic substrate surfaces, facilitating the growth of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) molecules by micro-spacing sublimation with liquid crystal properties. These hydrophobic lattice structures function as thermal stress release sites during the film cooling process, enabling the formation of organic single-crystal films with precisely controlled pore locations and sizes. The resulting porous films demonstrate electrical properties on stripes with those achieved through growing on bare silicon substrates, yet exhibit enhanced sensitivity, faster response times, and a lower detection limit when used as active layers in gas sensors. This technique offers a promising pathway for advancing high-performance organic gas sensors toward industrial application.

It has been proved to be an effective route to efficiently ameliorate photocatalytic performance of catalysts via designing three-dimensional (3D) hierarchical nanostructures and constructing oxygen vacancies (V_Os). However, controlling the self-assembly of organization into 3D hierarchical nanostructures while introducing V_Os in photocatalysts remains a challenge. Herein, we reported an ethylene glycol (EG) mediated approach to craft 3D hydrangea-structure Bi₂MoO₆ with V_Os for efficient photocatalytic degradation of tetracycline. Through manipulating the EG concentration during the fabrication process, the influence of EG concentration on the Bi₂MoO₆ structure was systematically investigated. EG could promote the self-assembly of Bi₂MoO₆ nanosheets to form a 3D hierarchical structure. Compared with 2D nanoplates, 3D hierarchical architecture enhanced the surface area and the amount of active sites of Bi₂MoO₆. In addition, the reduction effect of EG on metallic oxide enabled the generation of V_Os in Bi₂MoO₆. The V_Os adjusted the electronic structure of Bi₂MoO₆, which not only enhanced the light harvesting, but also facilitated the simultaneous utilization of photo-induced electrons and holes to form reactive oxygen species (·O²⁻ and ·OH) for the efficient tetracycline decomposition. 3D Bi₂MoO₆ hydrangea with V_Os achieved a 79.4% removal efficiency of tetracycline after 75 min. This work provides a simple yet robust EG-mediated strategy, which not only promotes the self-assembly of nano-catalysts into 3D hierarchical architectures, but also crafts tunable V_Os for highly efficient photocatalysis.