Langmuir−Schaeffer Films from a π−π Stacking Perylenediimide Dye: Organization and Charge Transfer Properties

Abstract

The organization of pi-pi stacking perylenediimide (PDI) derivative, PDI12, was studied in solution and in thin films. Films were prepared with the Langmuir-Schaeffer (LS) method and characterized by means of AFM, optical profilometry, steady-state absorption, emission, fluorescence lifetime, and transient photovoltage measurements. The columnar aggregates observed previously in PDI12 solutions and in spin-coated films persist also in LS films. Because of the specific conditions during the preparation of the LS film, i.e., hydrophobic interactions and lateral compression, the columnar aggregates seem to organize with their long axis perpendicular to the layer plane whereas in spin-coated films the columns were oriented parallel to the layer plane. According to AFM and profilometer results, the thickness of LS monolayer of PDI12 is 10 nm, indicating that it consists mainly of aggregates, each containing approximately 30 monomers. Intermolecular photoinduced energy and electron transfer processes in C(60)|PDI12 double layer junction were studied. The fluorescence lifetime of PDI12 film is exceptionally long, but the quenching is very efficient in the presence of C(60). In charge transfer studies, long-lived photovoltage signal was observed for the double layer. Results of this work indicate that PDI12 acts as an electron acceptor and fullerene C(60) as an electron donor.

Association phenomena of a chiral perylene derivative in solution and in poly(ethylene) dispersion

“…Nowadays perylene derivatives represent an extremely important class of organic dyes which are employed in several applications ranging from fluorescence standards [1][2][3], thin film transistors [4][5][6], liquid crystals [7][8][9], light emitting diodes [10], to photovoltaic devices [4,[10][11][12][13].…”

Miscibility of Perylene Derivatives with Fatty Acid in Two-Dimensional Binary Mixture

“…They are the mostly studied amphiphilic substances used as compound for gathering basic infor-* corresponding author; e-mail: tomasz.martynski@put.poznan.pl mation on the properties of the Langmuir monolayers [16]. Arachidic acid (AA) is an example of thoroughly characterized material in monolayers at the airwater interface.…”

Molecular organization of perylene derivatives in Langmuir–Blodgett multilayers

“…The profiles were best fitted with single exponential function and lifetime of 3.85 ns, the value in the range typically found in the literature for perylene monomer [10,22,34,35]. Table 3 Fluorescence lifetimes s i and fractional contribution C i of the components emission of investigated LB films.…”

“…In thin layer films created by spin-coating, drop-casting or Langmuir-Blodgett techniques, where solvent molecules evaporate, the self-organization phenomenon is even greater than in concentrated solutions [7,9,21,22,[29][30][31]. This is clearly observed by comparing absorption and luminescence spectra.…”

“…Perylene derivatives depending on hydrocarbon chains substituted in the lateral positions or/and atoms attached to the main perylene core have n or p semiconductor character [7,[13][14][15][16][17]. It was also shown that the length of hydrocarbon (alkoxy or alkyl) chains and the presence of halogen atoms in so-called bay positions have a great impact on the dye molecule aggregation in highly concentrated structures, such as thin films created with the use of different techniques or molecular crystals [7,[9][10][11][18][19][20][21][22][23][24]. The control of the molecular arrangement is necessary to create efficient optical devices characterized by high luminescence quantum yield and charge carriers' mobility at the same time.…”