High performance humidity sensors based on dopamine biomolecules coated gold-nanoparticles

This study presents a simple process for producing resistance-based humidity sensors utilizing dopamine (DA) coated gold nano-particles (AuNPs) as the sensing material. Highly hydrophilic bio-molecule of dopamine is physically bonded onto 4-6 nm AuNPs to enhance the humidity sensing performance. Results show that the DA coated AuNPs have nice humidity sensing responses in the measuring range of 20-90%RH. The measured resistance response shows >;1900 times greater than the sensor using the same AuNPs without DA coating. The developed humidity sensor shows rapid time responses for water absorption (5 s) and desorption (10 s), respectively. Moreover, a 3-day long-term measurement at low medium and high humidity ranges also shows the good stability of the developed sensor. The method developed in this study provides a simple and low-cost method to produce highperformance humidity sensors with DA-coated AuNPs.