TY - JOUR
T1 - Laser Direct Writing of a High-Performance All-Graphene Humidity Sensor Working in a Novel Sensing Mode for Portable Electronics
AU - Cai, Jinguang
AU - Lv, Chao
AU - Aoyagi, Eiji
AU - Ogawa, Sayaka
AU - Watanabe, Akira
PY - 2018/7/18
Y1 - 2018/7/18
N2 - This paper reports a fast and highly sensitive all-graphene humidity sensor working in a novel alternating current (ac) detection mode for the first time, which is capable of sensing humidity on a smartphone for portable electronics. The humidity sensor is based on an interdigitated reduced graphene oxide/graphene oxide/rGO (rGO/GO/rGO) structure patterned by a facile laser direct writing method. It works in an ac sensing mode with a rectangular input voltage wave and measures the output voltage wave instead of conventional resistance, impedance, or capacitance, exhibiting a dramatically enhanced sensitivity by about 45 times compared to the low and unstable response in dc mode. The humidity sensor shows an obvious response to the relative humidity (RH) ranging from RH 6.3% to RH 100%. The response and recovery toward humidity change are almost instantaneous, and the corresponding costed times including humidity rise and decay times are less than 1.9 and 3.9 s, respectively, which are among the best results in the literature. The sensor also exhibits outstanding cycling stability, flexibility, and long-term stability (>1 year), as well as good reproducibility of device preparation. Besides, it can be easily connected to an iPhone and the humidity sensing can be conducted with an oscilloscope application on iOS. What's more, an electronic circuit simulation method was employed to fit the output waves, which can not only explain the sensing mechanism, but also determine the resistance and capacitance of the rGO/GO/rGO structure, agreeing well with the results obtained from the electrochemical measurements. It can be reasonably expected that the approach combining humidity sensing and electronic circuit simulation can be applied in real-time monitoring on a smartphone based on the Internet of things and big data technologies.
AB - This paper reports a fast and highly sensitive all-graphene humidity sensor working in a novel alternating current (ac) detection mode for the first time, which is capable of sensing humidity on a smartphone for portable electronics. The humidity sensor is based on an interdigitated reduced graphene oxide/graphene oxide/rGO (rGO/GO/rGO) structure patterned by a facile laser direct writing method. It works in an ac sensing mode with a rectangular input voltage wave and measures the output voltage wave instead of conventional resistance, impedance, or capacitance, exhibiting a dramatically enhanced sensitivity by about 45 times compared to the low and unstable response in dc mode. The humidity sensor shows an obvious response to the relative humidity (RH) ranging from RH 6.3% to RH 100%. The response and recovery toward humidity change are almost instantaneous, and the corresponding costed times including humidity rise and decay times are less than 1.9 and 3.9 s, respectively, which are among the best results in the literature. The sensor also exhibits outstanding cycling stability, flexibility, and long-term stability (>1 year), as well as good reproducibility of device preparation. Besides, it can be easily connected to an iPhone and the humidity sensing can be conducted with an oscilloscope application on iOS. What's more, an electronic circuit simulation method was employed to fit the output waves, which can not only explain the sensing mechanism, but also determine the resistance and capacitance of the rGO/GO/rGO structure, agreeing well with the results obtained from the electrochemical measurements. It can be reasonably expected that the approach combining humidity sensing and electronic circuit simulation can be applied in real-time monitoring on a smartphone based on the Internet of things and big data technologies.
KW - ac sensing mode
KW - big data
KW - graphene oxide
KW - humidity sensor
KW - internet of things
KW - laser direct writing
UR - http://www.scopus.com/inward/record.url?scp=85049228529&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85049228529&partnerID=8YFLogxK
U2 - 10.1021/acsami.8b07373
DO - 10.1021/acsami.8b07373
M3 - Article
C2 - 29931979
AN - SCOPUS:85049228529
VL - 10
SP - 23987
EP - 23996
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 28
ER -