TY - JOUR
T1 - Long lifetime photoluminescence in N, S co-doped carbon quantum dots from an ionic liquid and their applications in ultrasensitive detection of pesticides
AU - Li, Haitao
AU - Sun, Chenghua
AU - Vijayaraghavan, Ranganathan
AU - Zhou, Fengling
AU - Zhang, Xinyi
AU - MacFarlane, Douglas R.
PY - 2016/8/1
Y1 - 2016/8/1
N2 - Pesticides widely used in modern agriculture can impact on the environment and human health and hence it is important to develop highly sensitive detectors for pesticide residues. Optical methods based on photoluminescence (PL) properties provide an ideal approach to facile and accurate trace-level analysis of pesticides. Carbon Quantum Dots (CQDs) have been proposed as the photo-sensitizer for this purpose, however the optical properties of pure CQDs restrict the detection limit of such an approach. Doping is an effective strategy to introduce novel electronic structure into the CQDs to solve this problem. Here, using ionic liquids as a single source, novel N and S co-doped CQDs were obtained by a simple ultrasonic method. The doping in the structure introduces localized states which can trap photo-excited electrons and enhance their PL lifetime. These quantum dots are successfully used as the basis of a simple, efficient sensor for ultrasensitive pesticide detection (Limit of Detection = 5 ppb). Application of the analysis method to real fruit samples is demonstrated. The mechanism of the high sensitivity is also investigated and explained from experimental and calculation results.
AB - Pesticides widely used in modern agriculture can impact on the environment and human health and hence it is important to develop highly sensitive detectors for pesticide residues. Optical methods based on photoluminescence (PL) properties provide an ideal approach to facile and accurate trace-level analysis of pesticides. Carbon Quantum Dots (CQDs) have been proposed as the photo-sensitizer for this purpose, however the optical properties of pure CQDs restrict the detection limit of such an approach. Doping is an effective strategy to introduce novel electronic structure into the CQDs to solve this problem. Here, using ionic liquids as a single source, novel N and S co-doped CQDs were obtained by a simple ultrasonic method. The doping in the structure introduces localized states which can trap photo-excited electrons and enhance their PL lifetime. These quantum dots are successfully used as the basis of a simple, efficient sensor for ultrasensitive pesticide detection (Limit of Detection = 5 ppb). Application of the analysis method to real fruit samples is demonstrated. The mechanism of the high sensitivity is also investigated and explained from experimental and calculation results.
UR - http://www.scopus.com/inward/record.url?scp=84962660488&partnerID=8YFLogxK
UR - http://ac.els-cdn.com.ezproxy.lib.monash.edu.au/S0008622316302226/1-s2.0-S0008622316302226-main.pdf?_tid=aa710904-9f13-11e6-8df7-00000aab0f26&acdnat=1477881929_73315c536a4f17d3324c72793b78b942
U2 - 10.1016/j.carbon.2016.03.040
DO - 10.1016/j.carbon.2016.03.040
M3 - Article
AN - SCOPUS:84962660488
VL - 104
SP - 33
EP - 39
JO - Carbon
JF - Carbon
SN - 0008-6223
ER -