Field-Effect Transistors Based on 2D Organic Semiconductors Developed by a Hybrid Deposition Method

Solution-processed 2D organic semiconductors (OSCs) have drawn considerable attention because of their novel applications from flexible optoelectronics to biosensors. However, obtaining well-oriented sheets of 2D organic materials with low defect density still poses a challenge. Here, a highly crystallized 2,9-didecyldinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (C₁₀-DNTT) monolayer crystal with large-area uniformity is obtained by an ultraslow shearing (USS) method and its growth pattern shows a kinetic Wulff's construction supported by theoretical calculations of surface energies. The resulting seamless and highly crystalline monolayers are then used as templates for thermally depositing another C₁₀-DNTT ultrathin top-up film. The organic thin films deposited by this hybrid approach show an interesting coherence structure with a copied molecular orientation of the templating crystal. The organic field-effect transistors developed by these hybrid C₁₀-DNTT films exhibit improved carrier mobility of 14.7 cm² V⁻¹ s⁻¹ as compared with 7.3 cm² V⁻¹ s⁻¹ achieved by pure thermal evaporation (100% improvement) and 2.8 cm² V⁻¹ s⁻¹ achieved by solution sheared monolayer C₁₀-DNTT. This work establishes a simple yet effective approach for fabricating high-performance and low-cost electronics on a large scale.