Correlation between Chain Packing and Photoluminescence for PPV/PPE in Macroscopically Oriented State:  Side Chain Effects

Abstract

Self-organization features of poly(p-phenylene-vinylene)/poly(p-phenylene-ethynylene)s (PPV/ PPE)s polymers of constitutional structure (-PhsCtCsPhsCtCsPhsCHdCHsPhsCHdCH-)n and bearing two alkoxy side chains on either every one (1) or every second (2) phenylene moieties are presented. Formation of self-assembled structures on various size scales has been examined using a combination of experimental methods. Initial investigations performed for macroscopically isotropic samples by means of DSC, POM, and 2D SALS have revealed a strong dependence of the thermal behavior and related morphologies on the side chain densities. The existence of organizational features in macroscopically oriented bulk samples (extruded filaments) was also demonstrated using 2D WAXS. Self-organization of (PPV/PPE)s into biphasic structures made of spatially segregated main chain layers with the side chains filling the space between layers was postulated. The local arrangement of the macromolecular subunits was strongly dependent on the macromolecular architecture and temperature. Two types of organization of the polymer chains assuming translationally correlated (2) and uncorrelated (1) positions could be distinguished. Fluorescence investigations using a frontal geometry setup were performed on the extruded filaments. Side-chain-dependent correlation between the structure and the photophysical behavior of PPV/ PPE could be established for the uniaxial orientation showing the bathochromic shift of the emission peak with the decrease of the interchain distances within layers.

Guest‐Triggered Supramolecular Isomerism in a Pillared‐Layer Structure with Unusual Isomers of Paddle‐Wheel Secondary Building Units by Reversible Single‐Crystal‐to‐Single‐Crystal Transformation

“…For details on the structural investigations including a sketch of the structure see Refs. 15, 16. These findings are in accordance with previous results showing that placement of anthracene between two double bonds (within the PPV units) leads to a distortion of the backbone.…”

“…Thermogravimetric analysis (TGA) was performed on a Mettler TA‐300‐thermal analyzer operating under air atmosphere. The π–π stacking distance, D π–π , was determined from wide‐angle X‐ray scattering measurements on extruded filaments as described elsewhere 15. The solid state absorption spectra were recorded on Varian UV/Vis spectrophotometer.…”

Synthesis and characterization of low bandgap conjugated donor–acceptor polymers for polymer:PCBM solar cells

“…[18][19][20]31,41 In order to further improve the efficiency of organic solar cells, it is necessary to have a deep understanding of the relationship between the polymer structure and their corresponding physical properties, especially of the influence of side-chains on device performance. Whereas the influence of side-chain length has been studied, [42][43][44][45] there are not many reports on the influence of sidechain position on photovoltaic performance. 20,46 In this study, three low-bandgap polymers with bis-N,N 0 -(4octylphenyl)-bis-N,N 0 -phenyl-1,4-phenylenediamine as one building block and one of three TBT (5,5-(4,7-di-2 0 -thienyl-2,1,3benzothiadiazole) derivatives as the other building block were synthesized.…”

Explaining the Cyclic Voltammetry of a Poly(1,4‐phenylene‐ethynylene)‐alt‐poly(1,4‐phenylene‐vinylene) Copolymer upon Oxidation by using Spectroscopic Techniques

“…An advantage of PPE is the low turn on voltage for OLEDs owing to the higher electron affinity compared with PPV . Moreover, poly(1,4‐phenylene‐ethynylene)‐ alt ‐poly(1,4‐phenylene‐vinylene) (PPE‐PPV) copolymers have attracted quite a lot of attention over the last few decades, because these copolymers combine the intrinsic properties of the PPE and PPV repeating units in a single polymeric backbone . Hence, new optoelectronic properties have been gained.…”

“…[10] Moreover,p oly(1,4-phenylene-ethynylene)-alt-poly(1,4-phenylene-vinylene) (PPE-PPV)c opolymers have attracted quite al ot of attentiono ver the last few decades, because these copolymers combine the intrinsic properties of the PPE and PPV repeating units in as ingle polymeric backbone. [11][12][13] Hence, new optoelectronic properties have been gained. These types of copolymers exhibit bathochromically shifteda bsorption and emission spectra as well as enhanced fluorescence quantum yields owing to reduced p-p interchaini nteractions in the solid state compared with PPEs.…”