Abstract
Shape-controlled synthesis of gold nanoparticles generally involves the use of surfactants, typically cetyltrimethylammonium (CTAX, X = Cl-, Br-), to regulate the nucleation growth process and to obtain colloidally stable nanoparticles. The surfactants adsorb on the nanoparticle surface making further functionalization difficult and therefore limit their use in many applications. Herein, the influence of CTAX on nanoparticle sensitivity to local dielectric environment changes is reported. It is shown, both experimentally and theoretically, that the CTAX bilayer significantly reduces the refractive index (RI) sensitivity of anisotropic gold nanoparticles such as nanocubes and concave nanocubes, nanorods, and nanoprisms. The RI sensitivity can be increased by up to 40% by removing the surfactant layer from nanoparticles immobilized on a solid substrate using oxygen plasma treatment. This increase compensates for the otherwise problematic decrease in RI sensitivity caused by the substrate effect. Moreover, the removal of the surfactants both facilitates nanoparticle biofunctionalization and significantly improves their catalytic properties. The strategy presented herein is a simple yet effective universal method for enhancing the RI sensitivity of CTAX-stabilized gold nanoparticles and increasing their potential as transducers in nanoplasmonic sensors, as well as in catalytic and biomedical applications.
| Original language | English |
|---|---|
| Pages (from-to) | 330-342 |
| Number of pages | 13 |
| Journal | Small |
| Volume | 12 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Jan 20 2016 |
Fingerprint
Keywords
- catalysis
- cetyltrimethylammonium
- finite-difference time-domain
- localized surface plasmon resonance
- oxygen plasma
ASJC Scopus subject areas
- Biomaterials
- Engineering (miscellaneous)
- Biotechnology
Cite this
Influence of Surfactant Bilayers on the Refractive Index Sensitivity and Catalytic Properties of Anisotropic Gold Nanoparticles. / Martinsson, Erik; Shahjamali, Mohammad M.; Large, Nicolas; Zaraee, Negin; Zhou, Yu; Schatz, George C; Mirkin, Chad A.; Aili, Daniel.
In: Small, Vol. 12, No. 3, 20.01.2016, p. 330-342.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Influence of Surfactant Bilayers on the Refractive Index Sensitivity and Catalytic Properties of Anisotropic Gold Nanoparticles
AU - Martinsson, Erik
AU - Shahjamali, Mohammad M.
AU - Large, Nicolas
AU - Zaraee, Negin
AU - Zhou, Yu
AU - Schatz, George C
AU - Mirkin, Chad A.
AU - Aili, Daniel
PY - 2016/1/20
Y1 - 2016/1/20
N2 - Shape-controlled synthesis of gold nanoparticles generally involves the use of surfactants, typically cetyltrimethylammonium (CTAX, X = Cl-, Br-), to regulate the nucleation growth process and to obtain colloidally stable nanoparticles. The surfactants adsorb on the nanoparticle surface making further functionalization difficult and therefore limit their use in many applications. Herein, the influence of CTAX on nanoparticle sensitivity to local dielectric environment changes is reported. It is shown, both experimentally and theoretically, that the CTAX bilayer significantly reduces the refractive index (RI) sensitivity of anisotropic gold nanoparticles such as nanocubes and concave nanocubes, nanorods, and nanoprisms. The RI sensitivity can be increased by up to 40% by removing the surfactant layer from nanoparticles immobilized on a solid substrate using oxygen plasma treatment. This increase compensates for the otherwise problematic decrease in RI sensitivity caused by the substrate effect. Moreover, the removal of the surfactants both facilitates nanoparticle biofunctionalization and significantly improves their catalytic properties. The strategy presented herein is a simple yet effective universal method for enhancing the RI sensitivity of CTAX-stabilized gold nanoparticles and increasing their potential as transducers in nanoplasmonic sensors, as well as in catalytic and biomedical applications.
AB - Shape-controlled synthesis of gold nanoparticles generally involves the use of surfactants, typically cetyltrimethylammonium (CTAX, X = Cl-, Br-), to regulate the nucleation growth process and to obtain colloidally stable nanoparticles. The surfactants adsorb on the nanoparticle surface making further functionalization difficult and therefore limit their use in many applications. Herein, the influence of CTAX on nanoparticle sensitivity to local dielectric environment changes is reported. It is shown, both experimentally and theoretically, that the CTAX bilayer significantly reduces the refractive index (RI) sensitivity of anisotropic gold nanoparticles such as nanocubes and concave nanocubes, nanorods, and nanoprisms. The RI sensitivity can be increased by up to 40% by removing the surfactant layer from nanoparticles immobilized on a solid substrate using oxygen plasma treatment. This increase compensates for the otherwise problematic decrease in RI sensitivity caused by the substrate effect. Moreover, the removal of the surfactants both facilitates nanoparticle biofunctionalization and significantly improves their catalytic properties. The strategy presented herein is a simple yet effective universal method for enhancing the RI sensitivity of CTAX-stabilized gold nanoparticles and increasing their potential as transducers in nanoplasmonic sensors, as well as in catalytic and biomedical applications.
KW - catalysis
KW - cetyltrimethylammonium
KW - finite-difference time-domain
KW - localized surface plasmon resonance
KW - oxygen plasma
UR - http://www.scopus.com/inward/record.url?scp=84955206604&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84955206604&partnerID=8YFLogxK
U2 - 10.1002/smll.201502449
DO - 10.1002/smll.201502449
M3 - Article
VL - 12
SP - 330
EP - 342
JO - Small
JF - Small
SN - 1613-6810
IS - 3
ER -