Abstract
The electrical and optical properties of thin films can be modulated by
its supramolecular arrangement being this latter closely related to the
fabrication method. Here, we are exploiting the impact of deposition
techniques of nickel phthalocyanine (NiPc) and tetrasulfonated nickel
phthalocyanine (NiTsPc) thin films on their supramolecular arrangement.
Deposition techniques as Langmuir-Schaffer (LS), Langmuir-Blodgett (LB),
physical vapor deposition (PVD), dipping- and spray-Layer-by-Layer (LbL)
were applied for fabrication of the thin films. Linear growth was
observed for all films indicating control of the amount of NiPc or
NiTsPc deposited in each technique at nm scale. Fourier-transform
infrared absorption spectroscopy (FTIR) and micro-Raman scattering
confirmed the chemical stability of NiPc and NiTsPc concerning the
deposition technique (water or heat). Besides, FTIR and X-ray
diffraction data suggested that all thin films present isotropy in terms
of molecular organization, with a predominance of the crystalline
a-phase in the case of PVD, LB, and LS films. Atomic force microscopy
images revealed irregularities at the surface for all thin film with the
roughness/thickness ratio being 4.5% for PVD, 9% for both LB and LS
films, and 18 and 35% for spray- and dipping-LbL films, respectively.
The electrochemical behavior in both inert electrolyte and dopamine (DA)
solution was directly dependent on the film morphology (molecular
aggregates and surface roughness). The increase of the roughness in
relation to thickness promoted films better electrochemical responses to
DA oxidation. The dipping-LbL films showed the smaller potential of DA
oxidation (0.114 V), even compared to the bare substrate (0.133 V). The
deposition technique showed to be an suitable tool to tune the
supramolecular arrangement of phthalocyanine forming thin films, which
improve and/or change the electrochemical properties of the device.
Users
Please
log in to take part in the discussion (add own reviews or comments).