Anthracene‐containing conjugated polymer showing four optical transitions upon doping: A spectroscopic study

Abstract

An anthracene-containing poly(arylene-ethynylene)alt-poly(arylene-vinylene) (PAE-PAV) of general constitutional unit (APhACBCAAnthrACBCAPhACH@CHAAnthrACH@CH) n bearing two 2-ethylhexyloxy solubilizing side chains on each phenylene (Ph) unit has been synthesized and characterized. The basic electrochemical characterization was done, showing the existence of two non-reversible oxidation and one reversible reduction peaks. The optical properties, the real and imaginary part of the dielectric function, were probed using spectroscopic ellipsometry (SE). The vibrational structure of the undoped/doped polymer was investigated using Fourier transformed infrared spectroscopy. A strong change in the polaronic absorption was observed during the doping, which after modeling revealed the existence of two separated transitions. The optical changes upon doping were additionally recorded using the SE technique. Similar to the results from FT-IR spectroscopy, two new in-the-gap absorptions were found. Moreover, the electrical conductivity as well as the mobility of positive carriers were measured. In the undoped state, the conductivity of the polymer was found to be below the detection limit (<lS cm 21 ), after doping the conductivity increased to 0.69 S cm 21 .

Band gap modulation in polythiophene and polypyrrole-based systems

“…Such transitions have been observed experimentally for doped π-conjugated polymers and supported by theoretical calculations for doped polythiophene. [28,53] The calculated values of the E binding are found to be similar to those of the monolayer counterparts, which means that the bonding of the atoms is quite similar for monolayer and bilayer. However, a significant variation in the valence and conduction band gap is found for mixed bilayers of polythiophene and polyselenophene or polythiophene and polytellurophene or polyselenophene and polytellurophene (compare Fig.…”

Structural and Electronic Properties of Pristine and Doped Polythiophene: Periodic versus Molecular Calculations

“…Experimentally, such a behavior has been detected for doped π-conjugated polymers. 62 Whereas, the binding energy is obtained to be −1.62 eV or −1.84 eV for Cl-intercalated bulk or bilayer polythiophene; again the data indicates that Cl intercalation in the bilayer case is energetically favorable by 0.21 eV. Moreover, the obtained value of the binding energy in case of bulk or bilayer is higher than that of monolayer polythiophene, which reflects that the binding of Li or Cl in bulk or bilayer is strong than that of monolayer polythiophene.…”

Polymers with alternating anthracene and phenylene building blocks linked by ethynylene and/or vinylene units: Studying structure‐properties‐relationships

“…The ellipsometric data were analyzed using specialized software (WVASE™). Details regarding SE measurement and modeling can be found elsewhere . For all polymers ( P1 – P4 ), the ψ and functions were modeled using generic oscillators, and specifically, a set of Lorentzian or Gaussian oscillators was used.…”

“…9,10‐Dibromoanthracene ( 1 ) was purchased from Sigma Aldrich. The synthesis of 2 , 3 , 4 , 5 , 7 , 8 , 9 , and P1 was performed according to the descriptions in literature.…”

“…Spectroscopic ellipsometry (SE) measurements were conducted to gain detailed insight into the optical properties of the various polymer configurations studied. SE is a widely used tool to investigate the optical properties of conjugated polymers in their pristine and doped states as well as in bulk heterojunction assemblies …”