TY - JOUR
T1 - Ultrasensitive detection of toxic cations through changes in the tunnelling current across films of striped nanoparticles
AU - Cho, Eun Seon
AU - Kim, Jiwon
AU - Tejerina, Baudilio
AU - Hermans, Thomas M.
AU - Jiang, Hao
AU - Nakanishi, Hideyuki
AU - Yu, Miao
AU - Patashinski, Alexander Z.
AU - Glotzer, Sharon C.
AU - Stellacci, Francesco
AU - Grzybowski, Bartosz A.
PY - 2012/11
Y1 - 2012/11
N2 - Although multiple methods have been developed to detect metal cations, only a few offer sensitivities below 1â €‰pM, and many require complicated procedures and sophisticated equipment. Here, we describe a class of simple solid-state sensors for the ultrasensitive detection of heavy-metal cations (notably, an unprecedented attomolar limit for the detection of CH 3 Hg + in both standardized solutions and environmental samples) through changes in the tunnelling current across films of nanoparticles (NPs) protected with striped monolayers of organic ligands. The sensors are also highly selective because of the ligand-shell organization of the NPs. On binding of metal cations, the electronic structure of the molecular bridges between proximal NPs changes, the tunnelling current increases and highly conductive paths ultimately percolate the entire film. The nanoscale heterogeneity of the structure of the film broadens the range of the cation-binding constants, which leads to wide sensitivity ranges (remarkably, over 18 orders of magnitude in CH 3 Hg + concentration).
AB - Although multiple methods have been developed to detect metal cations, only a few offer sensitivities below 1â €‰pM, and many require complicated procedures and sophisticated equipment. Here, we describe a class of simple solid-state sensors for the ultrasensitive detection of heavy-metal cations (notably, an unprecedented attomolar limit for the detection of CH 3 Hg + in both standardized solutions and environmental samples) through changes in the tunnelling current across films of nanoparticles (NPs) protected with striped monolayers of organic ligands. The sensors are also highly selective because of the ligand-shell organization of the NPs. On binding of metal cations, the electronic structure of the molecular bridges between proximal NPs changes, the tunnelling current increases and highly conductive paths ultimately percolate the entire film. The nanoscale heterogeneity of the structure of the film broadens the range of the cation-binding constants, which leads to wide sensitivity ranges (remarkably, over 18 orders of magnitude in CH 3 Hg + concentration).
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U2 - 10.1038/nmat3406
DO - 10.1038/nmat3406
M3 - Article
C2 - 22961202
AN - SCOPUS:84867808896
VL - 11
SP - 978
EP - 985
JO - Nature Materials
JF - Nature Materials
SN - 1476-1122
IS - 11
ER -