Volume 20, Issue 12 p. 3421-3426
Full Paper

Towards the Fabrication of the Top-Contact Electrode in Molecular Junctions by Photoreduction of a Metal Precursor

Dr. Santiago Martín,

Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 (Spain), Fax: +34 976761200

Instituto de Ciencias de Materiales de Aragón (ICMA), Universidad de Zaragoza-CSIC, 50009 Zaragoza (Spain)

Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza (Spain)

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Dr. Gorka Pera,

Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 (Spain), Fax: +34 976761200

Instituto de Nanociencia de Aragón (INA) edificio i+d Campus Rio Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza (Spain)

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Dr. Luz M. Ballesteros,

Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 (Spain), Fax: +34 976761200

Instituto de Nanociencia de Aragón (INA) edificio i+d Campus Rio Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza (Spain)

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Adam J. Hope,

Department of Chemistry, University of Durham, Durham DH1 3LE (UK)

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Santiago Marqués-González,

Department of Chemistry, University of Durham, Durham DH1 3LE (UK)

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Prof. Paul J. Low,

Department of Chemistry, University of Durham, Durham DH1 3LE (UK)

School of Chemistry and Biochemistry, University of Western Australia, 35 Stirling Highway, Crawley, Perth, 6009 (Australia)

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Prof. Francesc Pérez-Murano,

Instituto de Microelectrónica de Barcelona (IMB-CNM, CSIC), Campus UAB, 08193 Bellaterra (Spain)

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Prof. Richard J. Nichols,

Department of Chemistry, University of Liverpool, Crown Street, Liverpool, L69 7ZD (UK)

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Dr. Pilar Cea,

Corresponding Author

Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 (Spain), Fax: +34 976761200

Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza (Spain)

Instituto de Nanociencia de Aragón (INA) edificio i+d Campus Rio Ebro, Universidad de Zaragoza, C/Mariano Esquillor, s/n, 50018 Zaragoza (Spain)

Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, 50009 (Spain), Fax: +34 976761200Search for more papers by this author
First published: 13 February 2014
Citations: 11

Abstract

Film buffs: Langmuir films undergo anion metathesis when assembled on an aqueous HAuCl4 subphase. Subsequent transfer to solid supports gives well-formed Langmuir–Blodgett monolayers in which the trimethylsilyl group serves as the surface contacting group. Photoreduction of the monolayers leads to the formation of metallic gold nanoislands on the surface of the film (see scheme). The electrical properties of these devices have been determined.

Abstract

Langmuir films of 4-{[4-({4-[(trimethylsilyl)ethynyl]phenyl}ethynyl)phenyl]ethynyl} benzenaminium chloride ([1 H]Cl) undergo anion metathesis when assembled on an aqueous auric acid (HAuCl4) subphase. Subsequent transfer to solid supports gives well-formed Langmuir–Blodgett (LB) monolayers of [1 H]AuCl4 in which the trimethylsilyl group serves as the surface contacting group. Photoreduction of the aurate on these monolayers leads to the formation of metallic gold nanoislands, which were distributed over the surface of the film. Electrical properties of these nascent devices were determined by recording current–voltage (IV) curves with conductive atomic force microscopy (c-AFM) using the PeakForce tunneling AFM (PF-TUNA) mode. This gives consistent sigmoidal IV curves that are indicative of well-behaved junctions free of metallic filaments and short circuits. The photoreduction of a metal precursor incorporated onto monomolecular films is therefore proposed as an effective method for the fabrication of molecular junctions.