文摘
Solution-processed SnO<sub>2sub> colloidal quantum dots (CQDs) have emerged as an important new class of gas-sensing materials due to their potential for low-cost and high-throughput fabrication. Here we employed the design strategy based on the synergetic effect from highly sensitive SnO<sub>2sub> CQDs and excellent conductive properties of multiwalled carbon nanotubes (MWCNTs) to overcome the transport barrier in CQD gas sensors. The attachment and coverage of SnO<sub>2sub> CQDs on the MWCNT surfaces were achieved by simply mixing the presynthesized SnO<sub>2sub> CQDs and MWCNTs at room temperature. Compared to the pristine SnO<sub>2sub> CQDs, the sensor based on SnO<sub>2sub> quantum dot/MWCNT nanocomposites exhibited a higher response upon exposure to H<sub>2sub>S, and the response toward 50 ppm of H<sub>2sub>S at 70 °C was 108 with the response and recovery time being 23 and 44 s. Because of the favorable energy band alignment, the MWCNTs can serve as the acceptor of the electrons that are injected from H<sub>2sub>S into SnO<sub>2sub> quantum dots in addition to the charge transport highway to direct the electron flow to the electrode, thereby enhancing the sensor response. Our research results open an easy pathway for developing highly sensitive and low-cost gas sensors.