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.