Zinc oxide's' ability to absorb and emit ultraviolet light has long been the operational foundation of photoelectric smoke detectors.
While this technology has proved effective in detecting larger smoke particles found in dense smoke, it’s not quite as sensitive in detecting the small smoke particles produced by fast burning fires.
Now researchers at the University of Surrey’s Advanced Technology Institute have dramatically increased the effective surface area of zinc oxide by fashioning the material into what amounts to nanowire "brushes," making the smoke detectors they’re used in 10,000 times more sensitive to UV light than a traditional zinc-oxide detector.
“UV light detectors made from zinc oxide have been used widely for some time but we have taken the material a step further to massively increase its performance," said Professor Ravi Silva, co-author of the study and head of the Advanced Technology Institute, in a press release. "Essentially, we transformed zinc oxide from a flat film to a structure with bristle-like nanowires, increasing surface area and therefore increasing sensitivity and reaction speed.”
In research published in the journal Scientific Reports, the researchers developed a method by which the zinc oxide nanowires would self-assemble directly on the chip. By carefully manipulating the concentration of chemicals used and the growth time, the researchers were able to boost the smoke detector’s performance, improving both the sensitivity and the response time.
Beyond just improving the performance of smoke detectors, the researchers believe that this research could impact a number of other application areas. The obvious candidates would be in gas detection and pollution monitoring. But the researchers see that this technology could be extended to phones and tablets to monitor our immediate personal environment. Silva says that it could even find application in future flexible electronic devices.
Added Silva: “This is a great example of a bespoke, designer nanomaterial that is adaptable to personal needs, yet still affordable.”
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.