Phenylselenol Healing Selenium Vacancies of Solution-Processed Tungsten Diselenide Enables High-Performance P-Type Thin-Film Transistors

Solution-processed semiconducting 2D single-crystal nanosheets with dangling-bond-free surfaces are tremendously promising in cost-effective and scalable printed (opto)electronic devices. Nevertheless, the scarcity of solution-processed p-type 2D semiconducting materials with high mobility remains a significant impediment to the advancement of thin-film transistors (TFTs) and, by extension, the development of complementary integrated circuits. In this work, we introduce a molecular approach to enhance the electrical performance of p-type tungsten diselenide van der Waals thin-film devices by employing phenylselenol modification. First, phenylselenol can effectively heal selenium vacancies in WSe₂ nanosheets, thereby enhancing their crystallinity and, consequently, improving the overall quality of WSe₂ thin film. In addition, the interface contact and energy-level structure between the WSe₂ thin film and the metal electrode are optimized, thereby reducing the Schottky barrier height for hole transportation. As a result, the WSe₂ TFTs exhibit a significant enhancement in hole mobility, reaching 35.22 cm² V^-1 s^-1. This simple yet effective strategy for improving the electrical performance of WSe₂ TFTs opens avenues for the development of advanced large-area logic technologies based on transition-metal dichalcogenide (TMD) semiconductors.