Wang, H.; Delacroix, S.; Zieleniewska, A.; Hou, J.; Tarakina, N.V.; Cruz, D.; Lauermann, I.; Ferguson, A.J.; Blackburn, J.L.; Strauss, V.: In Situ Synthesis of Molybdenum Carbide Nanoparticles Incorporated into Laser-Patterned Nitrogen-Doped Carbon for Room Temperature VOC Sensing. Advanced Functional Materials 31 (2021), p. 2104061/1-11
10.1002/adfm.202104061
Open Access Version
Abstract:
Carbon laser-patterning (CLaP) is emerging as a new tool for the precise and selective synthesis of functional carbon-based materials for on-chip applications. The aim of this work is to demonstrate the applicability of laser-patterned nitrogen-doped carbon (LP-NC) for resistive gas-sensing applications. Films of pre-carbonized organic nanoparticles on polyethylenetherephthalate are carbonized with a CO2-laser. Upon laser-irradiation a compositional and morphological gradient in the films is generated with a carbon content of 92% near the top surface. The specific surface areas of the LP-NC are increased by introducing sodium iodide (NaI) as a porogen. Electronic conductivity and surface area measurements corroborate the deeper penetration of the laser-energy into the film in the presence of NaI. Furthermore, impregnation of LP-NC with MoC1-x (<10 nm) nanoparticles is achieved by addition of ammonium heptamolybdate into the precursor film. The resulting doping-sensitive nano-grain boundaries between p-type carbon and metallic MoC1-x lead to an improvement of the volatile organic compounds sensing response of Delta R/R0 = -3.7% or -0.8% for 1250 ppm acetone or 900 ppm toluene at room temperature, respectively, which is competitive with carbon-based sensor materials. Further advances in sensitivity and in situ functionalization are expected to make CLaP a useful method for printing selective sensor arrays.