Cadmium telluride/polypyrrole (CdTe/PPy) nanocomposites are synthesized and integrated into Love mode surface acoustic wave (L SAW) sensors, achieving high sensitivity to various volatile organic compounds including acetone, ethanol, and toluene. Chemical/physical analysis of the composites and their integration as second/guiding sensitive layer into the L SAW structure show no evidence of strong chemical interaction among the structural components based on CdTe quantum dots and PPy nanoparticles. The gas sensing tests are focus on the performance of L SAW sensors consisting of CdTe/PPy (1:10), CdTe/PPy (1:2), and non-modified PPy layers. Results reveal that the L SAW sensors containing CdTe/PPy (1:10) composite improve the sensing performances to acetone showing a sensitivity of 771 Hz/ppm, an estimated limit of detection (LOD) of 5 ppb, and low interference to ethanol and toluene, compared to the sensors with CdTe/PPy (1:2) or without CdTe modification. The high sensitivity of the L SAW sensors to acetone is connected with the adsorption of acetone at PPy via dipole-dipole interaction and the incorporation of CdTe in the guiding/sensitive L SAW layers.
Keywords: Polypyrrole, Quantum dots, Composite, Surface acoustic wave, Gas sensors.
This work has been supported in part by the Czech Science Foundation (GAČR) via Grant No. 20-20123S, the Spanish Ministry of Economy and Competitiveness via projects TEC2015-74329-JIN-(AEI/FEDER, EU), and TEC2016-79898-C6-1-R (AEI/FEDER, EU) and by Universidad Nacional Autónoma de México via Grant DGAPA-UNAM-PAPIIT TA100118. The support of the Ramón y Cajal programme is also acknowledged. This research has made use of the infrastructures of the Spanish ICTS Network MICRONANOFABS, partially supported by MINECO, and Czech CEITEC Nano Research Infrastructure, supported by MEYS CR (LM2018110). We are grateful to Tomas Lednicky for supporting us with the profilometry measurements.