Zinc oxide optical and chemical sensors fabricated by inkjet printing and drop casting

摘要

Nanoparticle solutions can be tailor-made to sense different wavelengths of light or the presense of various chemicals, and are promising for next generation sensors. But these "inks" are incompatible with traditional manufacturing techniques, so consistent fabrication remains a challenge. Drop casting and inkjet printing are promising techniques for large scale, cost effective fabrication of nanoparticle sensors. To explore these processes, zinc oxide (ZnO) coatings were drop cast and printed onto pre-patterened substrates to form photo-resistive and chemo-resistive devices. The devices were tested for sensitivity to ultraviolet (UV) light and H_2, N_2, and NH_3 gasses. The drop cast devices were found to be sensitive to all four stimuli and appeared to show chemical selectivity. The inkjet devices were found to be sensitive to UV light and showed good uniformity over 1 cm~2 devices. The inkjet devices were less chemically sensitive than the drop cast devices due to device design. Some critical characteristics for improved performance are identified and discussed.