Indium–chlorine and gallium–chlorine tetrasubstituted phthalocyanines in a bulk system, Langmuir monolayers and Langmuir–Blodgett nanolayers – Spectroscopic investigations B. Bursa a , D. Wróbel a,⇑ , A. Biadasz a , K. Ke ˛ dzierski a , K. Lewandowska b , A. Graja b , M. Szybowicz c , M. Durmus ß d a Faculty of Technical Physics, Institute of Physics, Poznan University of Technology, 60-965 Poznan ´, Poland b Institute of Molecular Physics, Polish Academy of Sciences, 60-179 Poznan ´, Poland c Faculty of Technical Physics, Chair of Optical Spectroscopy, Poznan University of Technology, 60-965 Poznan ´, Poland d Gebze Institute of Technology, Department of Chemistry, Gebze 41400, Turkey highlights  Electronic, FTIR, Raman spectra of In- ClTPc and Ga-ClTPc in chloroform and in situ light absorption of Langmuir monolayers.  In-ClTPc forms the oblige cooplanar aggregate while Ga-ClTPc creates the H-type aggregate.  The dyes in Langmuir–Blidgett layers are oriented nearly vertically in relation to the gold substrate. graphical abstract article info Article history: Received 21 October 2013 Received in revised form 18 February 2014 Accepted 23 February 2014 Available online 12 March 2014 Keywords: Metallic phthalocyanine In situ light absorption measurements UV–Vis–NIR–IR–Raman spectra Langmuir, Langmuir–Blodgett layer Molecular aggregation abstract The paper deals with spectroscopic characterization of metallic phthalocyanines (Pc’s) (indium and gal- lium) complexed with chlorine and substituted with four benzyloxyphenoxy peripheral groups in bulk systems, 2D Langmuir monolayers and Langmuir–Blodgett nanolayers. An influence of the molecular structure of dyes (the presence of metal and of substitutes attached to the phthalocyanine macroring) on the in situ measurements of light absorption is reported. Molecular arrangement of the phthalocyanine molecular skeleton in the Langmuir monolayers on water substrate and in the Langmuir–Blodgett nano- layers is evaluated. A comparison of the light absorption spectra of the phthalocyanine monolayers with the spectra of the dyes in solution supports the existence of dye aggregates in the monolayer. It was shown that the type of dye aggregates (oblique and H types) depends markedly on the dye molecular structures. The NIR-IR, IR reflection–absorption and Raman spectra are also monitored for Langmuir– Blodgett nanolayers in non-polarized and polarized light. It was shown that the dye molecules in the Langmuir–Blodgett layers are oriented nearly vertically with respect to a gold substrate. Ó 2014 Elsevier B.V. All rights reserved. Introduction Since the past decades phthalocyanines have been a subject of numerous papers because of their unique spectroscopic, photo- electric and magnetic properties [1]. Pc’s are usually characterized http://dx.doi.org/10.1016/j.saa.2014.02.178 1386-1425/Ó 2014 Elsevier B.V. All rights reserved. Abbreviations: Pc, phthalocyanine; Ga-ClTPc, gallium–chlorine benzyloxyphen- oxy phthalocyanine; In-ClTPc, indium–chlorine benzyloxyphenoxy phthalocyanine; L, Langmuir; LB, Langmuir–Blodgett; DMSO, dimethyl sulfoxide; HWFM, half width at full maximum; IR, infrared; IRRA, infrared reflection-absorption. ⇑ Corresponding author. Tel.: +48 616653179; fax: +48 616653178. E-mail address: danuta.wrobel@put.poznan.pl (D. Wróbel). Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 128 (2014) 489–496 Contents lists available at ScienceDirect Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal homepage: www.elsevier.com/locate/saa