Tetrakis(4-sulfonatophenyl)porphyrin-directed assembly of gold nanocrystals: tailoring the plasmon coupling through controllable gap distances.
It is known that universality and controllability over nanocrystal orientation must be accomplished to facilitate the potential applications of metal nanocrystals in the areas of photonics, electronics, and optics. The facile fabrication of linear chains of Au nanorods and bifurcated junctions of nanorods/nanospheres is achieved via the crosslinking of H-type tetrakis(4-sulfonatophenyl)porphyrin aggregates in solution. The tuning of the plasmon coupling between the Au nanocrystals is demonstrated by varying the porphyrin concentration and thus the interparticle gap distances. Finite-difference time-domain calculations show that the red shift of the plasmon band exhibits a nearly exponential decay with increasing interparticle gap distances, thus giving rise to a "plasmon ruler equation." The gap distances determined according to this equation agree well with the experimental observations and further confirm the porphyrin-directed assembly process. The interaction mechanism between the Au nanorods and porphyrins is further investigated by a biological procedure using the dark-field light scattering technique.
Zhang
Li
L
College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
Chen
Huanjun
H
Wang
Jianfang
J
Li
Yuan Fang
YF
Wang
Jian
J
Sang
You
Y
Xiao
Sai Jin
SJ
Zhan
Lei
L
Huang
Cheng Zhi
CZ
D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D008958:Models, Molecular; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D020349:Surface Plasmon Resonance / Q000379:methods; D013499:Surface Properties
D011108:Polymers; D011166:Porphyrins; C016136:tetraphenylporphine sulfonate; D006046:Gold