Details

Autor(en) / Beteiligte

• Adams, Sarah M.
• Campione, Salvatore
• Caldwell, Joshua D.
• Bezares, Francisco J.
• Culbertson, James C.
• Capolino, Filippo
• Ragan, Regina

Titel

Non-lithographic SERS Substrates: Tailoring Surface Chemistry for Au Nanoparticle Cluster Assembly

Ist Teil von

• Small (Weinheim an der Bergstrasse, Germany), 2012-07, Vol.8 (14), p.2239-2249

Ort / Verlag

Weinheim: WILEY-VCH Verlag

Erscheinungsjahr

2012

Link zum Volltext

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• Near‐field plasmonic coupling and local field enhancement in metal nanoarchitectures, such as arrangements of nanoparticle clusters, have application in many technologies from medical diagnostics, solar cells, to sensors. Although nanoparticle‐based cluster assemblies have exhibited signal enhancements in surface‐enhanced Raman scattering (SERS) sensors, it is challenging to achieve high reproducibility in SERS response using low‐cost fabrication methods. Here an innovative method is developed for fabricating self‐organized clusters of metal nanoparticles on diblock copolymer thin films as SERS‐active structures. Monodisperse, colloidal gold nanoparticles are attached via a crosslinking reaction on self‐organized chemically functionalized poly(methyl methacrylate) domains on polystyrene‐block‐poly(methyl methacrylate) templates. Thereby nanoparticle clusters with sub‐10‐nanometer interparticle spacing are achieved. Varying the molar concentration of functional chemical groups and crosslinking agent during the assembly process is found to affect the agglomeration of Au nanoparticles into clusters. Samples with a high surface coverage of nanoparticle cluster assemblies yield relative enhancement factors on the order of 109 while simultaneously producing uniform signal enhancements in point‐to‐point measurements across each sample. High enhancement factors are associated with the narrow gap between nanoparticles assembled in clusters in full‐wave electromagnetic simulations. Reusability for small‐molecule detection is also demonstrated. Thus it is shown that the combination of high signal enhancement and reproducibility is achievable using a completely non‐lithographic fabrication process, thereby producing SERS substrates having high performance at low cost. Au nanoparticles from colloids are assembled in clusters on chemically patterned polymer surfaces using surface chemical reactions, thus providing a versatile assembly method for metal nanoarchitectures. Surface‐enhanced Raman scattering (SERS) measurements on samples with a high density of clusters exhibit uniform enhancement factors as high as 109 across the sample and are reusable for the detection of SERS‐active molecules.