Porphycene Films Grown on Highly Oriented Pyrolytic Graphite: Unveiling Structure–Property Relationship through Combined Reflectance Anisotropy Spectroscopy and Atomic Force Microscopy Investigations
Marta Penconi,
Lorenzo Ferraro,
Jacek Waluk,
Lamberto Duò,
Franco Ciccacci,
Alberto Bossi,
Marcello Campione,
Gianlorenzo Bussetti
Affiliations
Marta Penconi
Consiglio Nazionale delle Ricerche, Istituto di Scienze e Tecnologie Chimiche “G. Natta” (CNR-SCITEC) and SmartMatLabCenter, via Fantoli 16/15, 20138 Milan, Italy
Lorenzo Ferraro
Department of Physics, Politecnico di Milano, p.za Leonardo da Vinci 32, 20133 Milan, Italy
Jacek Waluk
Faculty of Mathematics and Science, Cardinal Stefan Wyszyński University, Dawajtis 5, 01-815 Warsaw, Poland
Lamberto Duò
Department of Physics, Politecnico di Milano, p.za Leonardo da Vinci 32, 20133 Milan, Italy
Franco Ciccacci
Department of Physics, Politecnico di Milano, p.za Leonardo da Vinci 32, 20133 Milan, Italy
Alberto Bossi
Consiglio Nazionale delle Ricerche, Istituto di Scienze e Tecnologie Chimiche “G. Natta” (CNR-SCITEC) and SmartMatLabCenter, via Fantoli 16/15, 20138 Milan, Italy
Marcello Campione
Department of Earth and Environmental Sciences, Università degli Studi di Milano-Bicocca, p.za della Scienza 4, 20126 Milan, Italy
Gianlorenzo Bussetti
Consiglio Nazionale delle Ricerche, Istituto di Scienze e Tecnologie Chimiche “G. Natta” (CNR-SCITEC) and SmartMatLabCenter, via Fantoli 16/15, 20138 Milan, Italy
Thin organic films are widely used in sensors, solar cells, and optical devices due to their intense absorption in the visible/near-infrared (IR) region. Shifting, quenching, or reshaping of some spectral features can be achieved by chemical functionalization of the molecules, whereas an anisotropic fingerprint due to preferential molecular alignment can be induced via a proper design and/or preparation of the substrate. Recently, we investigated the optical response of thin films of porphycene to acidification. With respect to the well-known and closely related tetraphenyl porphyrin, porphycene has the clear advantage of being optically active in the full visible range, and this makes visible by naked eye the immediate change of the film from brilliant blue-turquoise to green when exposed to HCl vapors. In this work, by exploiting a homemade reflectance anisotropy spectroscopy (RAS) apparatus, we explore possible optical anisotropies in the visible spectral range of porphycene films and relate them to the film morphology analyzed by atomic force microscopy (AFM).
