TY - JOUR

T1 - Characterization and conductivity of Langmuir-Blodgett films prepared from an amine substituted oligo(phenylene ethynylene)

AU - Villares, Ana

AU - Lydon, Donocadh

AU - Low, Paul

AU - Robinson, Benjamin

AU - Ashwell, Geoff

AU - Royo, Felix

AU - Pilar, Cea

PY - 2008/1/8

Y1 - 2008/1/8

N2 - This paper reports the assembly of well-defined molecular films from 4-[4-(4-hexyloxyphenylethynyl)-phenylethynyl]-aniline (HBPEB amine), an oligomeric phenylene ethynylene (OPE) derivative, by means of the Langmuir–Blodgett technique. Initially, Langmuir films of HBPEB amine were prepared at the air–water interface and characterized with surface pressure vs area per molecule isotherms. Brewster Angle Microscopy was used to map the different phases of the monolayer at the air–water interface. UV–vis reflection spectroscopy showed a blue shift of 20 nm of the reflection spectrum of the Langmuir film with respect to the spectrum of a chloroform solution of HBPEB amine, which indicates that two-dimensional H-aggregates are formed at the air–water interface. The monolayers were transferred onto solid substrates with a Y-type deposition and a transfer ratio of 1. The excellent transfer characteristics permitted the construction of films comprising up to 150 layers, with a uniform architecture. The LB films fabricated from HBPEB amine show a blue shift of ca. 30 nm with respect to the chloroform solution of HBPEB amine, likely arising from a change in the orientation of the molecular transition dipole with respect to the surface normal in the solid-supported films in comparison with the Langmuir films at the air–water interface. The current–voltage (I−V) characteristics of LB monolayers are unexpectedly symmetrical, the asymmetric contacts not being apparent from the observed I−V characteristics.

AB - This paper reports the assembly of well-defined molecular films from 4-[4-(4-hexyloxyphenylethynyl)-phenylethynyl]-aniline (HBPEB amine), an oligomeric phenylene ethynylene (OPE) derivative, by means of the Langmuir–Blodgett technique. Initially, Langmuir films of HBPEB amine were prepared at the air–water interface and characterized with surface pressure vs area per molecule isotherms. Brewster Angle Microscopy was used to map the different phases of the monolayer at the air–water interface. UV–vis reflection spectroscopy showed a blue shift of 20 nm of the reflection spectrum of the Langmuir film with respect to the spectrum of a chloroform solution of HBPEB amine, which indicates that two-dimensional H-aggregates are formed at the air–water interface. The monolayers were transferred onto solid substrates with a Y-type deposition and a transfer ratio of 1. The excellent transfer characteristics permitted the construction of films comprising up to 150 layers, with a uniform architecture. The LB films fabricated from HBPEB amine show a blue shift of ca. 30 nm with respect to the chloroform solution of HBPEB amine, likely arising from a change in the orientation of the molecular transition dipole with respect to the surface normal in the solid-supported films in comparison with the Langmuir films at the air–water interface. The current–voltage (I−V) characteristics of LB monolayers are unexpectedly symmetrical, the asymmetric contacts not being apparent from the observed I−V characteristics.

U2 - 10.1021/cm702532m

DO - 10.1021/cm702532m

M3 - Journal article

VL - 20

SP - 258

EP - 264

JO - Chemistry of Materials

JF - Chemistry of Materials

SN - 0897-4756

IS - 1

ER -