Molecular Sensitizer-Loaded Monolayer Organic Semiconductors for High-Performance H₂S Sensors

Monolayer organic semiconductors offer high gas sensitivity due to their exposed active channels and absence of grain boundaries, allowing them to interact directly with the analytes. However, such single-component organic sensors are typically lacking in selective adsorption sites, leading to practical hindrances such as limited chemical selectivity and slow recovery. In this study, we demonstrate a highly crystalline monolayer C₁₀-DNTT semiconductor film sensitized with F₄-TCNQ (F₄-TCNQ/C₁₀-DNTT), fabricated using a one-step solution-shearing codeposition method, which overcomes the aforementioned challenges to serve as a high-performance chemical gas sensor. Compared to pristine C₁₀-DNTT, the monolayer F₄-TCNQ/C₁₀-DNTT films showed an enhanced response to hydrogen sulfide (H₂S), an industrial pollutant and an important biomarker for respiratory disorders, as the sensitizer molecules promoted electronic interactions at the gas-organic semiconductor interface. Specifically, this resulted in a 5.3-fold increase in sensitivity to 5 ppm of H₂S, with high selectivity and improved recovery compared to pristine C₁₀-DNTT sensors. The precisely defined two-dimensional (2D) structure of the F₄-TCNQ/C₁₀-DNTT films enabled the investigation of layer-dependent sensing characteristics, reinforcing the significance of the monolayer configuration for achieving highly sensitive and selective H₂S sensing. This research provides an effective strategy for designing high-performance organic sensing devices and highlights the importance of layer precision in sensor response, contributing to the development of more efficient and reliable organic chemical sensors in the future.