Optical and morphological properties of ultra‐thin H2TPP, H4TPP and ZnTPP films. Issue 1 (16th April 2014)

• Record Type: Journal Article
• Authors: Bussetti, Gianlorenzo; Campione, Marcello; Sassella, Adele; Duò, Lamberto
• Is Part Of: Physica status solidi. Volume 252:Issue 1(2015:Jan.)
• Page Start: 100
• Page End: 104
• Publication Date: 2014-04-16
• Subjects: Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.201350260
• Languages: English
• ISSNs: 0370-1972

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="pssb201350260-sec-0001" sec-type="section"> <p>An interesting and well known chemical reaction (tautomerism) in free‐base porphyrins (namely H₂TPP) has been considered promising for application in organic electronics. Recently, we have proposed an original strategy to obtain a pure 2D layer of H₂TPP molecules, where tautomers are aligned along the same direction, inducing anisotropy in the porphyrin optical transitions. This opens the route to an organic optical device if the tautomer signal can be inhibited and restored in a controlled mode. Here, we demonstrate that, conversely to H₂TPP film, the di‐acid H₄TPP sample, easily reachable from free‐base porphyrins, shows almost isotropic transitions. The change of the optical spectral intensities between H₂TPP and H₄TPP samples, as detected by reflectance anisotropy spectroscopy (RAS), is interpreted in terms of two distinct logic states. Furthermore, RAS spectra acquired both on the H₂TPP and the H₄TPP samples are compared with the optical spectra of ultra‐thin films of ZnTPP, the latter being a genuine isotropic porphyrin.</p> </sec> </abstract>