Hybrid liquid crystalline zinc phthalocyanine@Cu2O nanowires for NO2 sensor application

A novel organic-inorganic hybrid conductometric NO2 sensor has been introduced by depositing liquid crystalline zinc oktakisalkylthiophthalocyanine [(C6S)(8)PcZn] on the surface of Cu2O nanowires. Cu2O nano wires were synthesized by electrochemical anodization of Cu films on glass substrates. Surface structures of bare Cu2O and (C6S)(8)PcZn@Cu2O nanowires hybrid structures were monitored by scanning electron microscope (SEM). UV-vis spectrophotometer measurements revealed the heterostructure formation by comparing the absorption profiles of bare Cu2O nanowires, (C6S)(8)PcZn thin film, and (C6S)(8)PcZn@Cu2O hybrid nanowires. The interdigitated transducers (IDT) were used for conductometric gas measurements. The sensing properties of all samples were investigated towards 500 ppb, 1 ppm, 2 ppm, and 5 ppm NO2 under dry airflow in 30 degrees C, 50 degrees C, 100 degrees C, and 150 degrees C. The measurements at 150 degrees C were repeated for (C6S)(8)PcZn film and hybrid sample using the same concentrations of NO2 gas under 38 % relative humidity airflow. In addition, selectivity of hybrid sensor was confirmed with carbon monoxide (CO), hydrogen (H-2) and ethanol (C2H5OH) measurements. Our density functional theory calculations indicate that S atoms play a crucial role in improving the sensor response. The sensing properties and sensing mechanisms of samples were compared and discussed.

Automated summary

A novel organic-inorganic hybrid conductometric NO2 sensor was introduced by depositing liquid crystalline zinc oktakisalkylthiophthalocyanine on the surface of Cu2O nanowires. The sensing properties towards NO2 under different conditions were investigated, and the structures and performances of materials were characterized by SEM and UV-vis spectrophotometer.