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Tetrakis(4‐sulfonatophenyl)porphyrin‐Directed Assembly of Gold Nanocrystals: Tailoring the Plasmon Coupling Through Controllable Gap Distances
Author(s) -
Zhang Li,
Chen Huanjun,
Wang Jianfang,
Li Yuan Fang,
Wang Jian,
Sang You,
Xiao Sai Jin,
Zhan Lei,
Huang Cheng Zhi
Publication year - 2010
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201090062
Subject(s) - porphyrin , nanorod , nanocrystal , materials science , plasmon , nanotechnology , photonics , band gap , chemical physics , optoelectronics , photochemistry , chemistry
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.