Measurements of HOMO-LUMO levels of poly(3-hexylthiophene) thin films by a simple electrochemical method

Acevedo–Peña, Próspero; Baray-Calderón, Alejandro; Hu, Hailin; González, Ignacio; Ugalde‐Saldívar, Víctor M.

doi:10.1007/s10008-017-3587-2

Cited by 36 publications

(21 citation statements)

References 34 publications

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“…Aiming to facilitate such analysis, Figure illustrates the alignment of the frontier levels of the evaluated polymers in relation to the HOMO and LUMO of typical acceptor compounds, as well as the work functions of electrodes commonly employed (or at least proposed) in flexible devices . In order to allow direct comparisons, our theoretical results for the HOMO values of the free MEH‐PPV and P3HT models were shifted to match the experimental HOMO values typically found in polymeric solutions of MEH‐PPV and P3HT …”

Section: Resultsmentioning

confidence: 99%

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Effects of Mechanical Stretching on the Properties of Conjugated Polymers: Case Study for MEH‐PPV and P3HT Oligomers

Roldao

Batagin‐Neto

Lavarda

et al. 2018

J Polym Sci B Polym Phys

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Nowadays, the development of new materials for applications in flexible optoelectronic devices is one of the main frontiers of science. However, in order to improve the applicability and durability of such devices, a deeper understanding of the effects induced by mechanical deformations on the properties of their components is still necessary. In this sense, in the present study, it is evaluated the effect of mechanical stretching in the structural, electronic, and optical responses of two widely investigated organic polymers with great technological interest: poly(2-methoxy,5-(2 0ethylhexyloxy)-1,4-phenylene vinylene) and poly(3-hexylthiophene-2,5-diyl). Hartree-Fock and density functional theory electronic structure calculation methods were employed for the study of oligomeric structures subjected to increasing stretch levels along the polymerization axis. The results show a dependence of the polymer properties with the mechanical deformation, allowing to identify distinct response regimes according to the main chain stretching. In particular, it is noticed that large stretches lead to nonfunctional devices, mainly due to the localization of the frontier orbitals and degradation of optoelectronic properties. In addition, it was also identified that very small deformations can lead to some interesting optoelectronic responses, which could indicate an alternative route for the design of organic devices via mechanical processes.

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Section: Resultsmentioning

confidence: 99%

“…Alignments between the frontier energy levels of the polymers and the frontier levels/work functions of typical acceptors and electrodes employed in flexible organic devices . [Color figure can be viewed at wieyonlinelibrary.com] …”

Section: Resultsmentioning

confidence: 99%

Effects of Mechanical Stretching on the Properties of Conjugated Polymers: Case Study for MEH‐PPV and P3HT Oligomers

Roldao

Batagin‐Neto

Lavarda

et al. 2018

J Polym Sci B Polym Phys

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“…Although P3HT is one of the more commonly studied CPs, there is still a broad range of reported HOMO and LUMO energies as measured with cyclic voltammetry (CV), with the LUMO energies ranging from À3.53 to À2.70 eV and the HOMO energies spanning a more narrow range from À4.92 to À5.20 eV versus vacuum. [38][39][40] These variations in measured energies could be the result of many different factors, including CP film preparation, choice of electrolyte, and solvent system. 39 Here, we investigate how counterion structure impacts the electrochemical doping ability, oxidation potential, polaron absorbance, and ionization energy of regioregular (rr) and regiorandom (rra) P3HT.…”

Section: Introductionmentioning

confidence: 99%

Impact of the anion on electrochemically doped regioregular and regiorandom poly(3‐hexylthiophene)

Baustert

Abtahi

Ayyash

et al. 2021

Journal of Polymer Science

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Chemical and electrochemical doping of π-conjugated polymers is an important aspect in determining the performance and enabling the operation of many organic electronic devices, from organic light emitting diodes and thermoelectrics to organic electrochemical transistors. In both chemical doping and electrochemical doping an ionized dopant or counterion is present along with the doped π-conjugated polymer. This dopant or counterion is not a benign spectator, rather, its presence can significantly impact the optical, electronic, and thermoelectric properties of the resulting material. Here, we investigate how counterion structure impacts the electrochemical doping ability, oxidation potential, ionization energy, and polaron absorbance of regioregular (rr) and regiorandom (rra) P3HT. We find that in most cases the anion has a small effect on the polymer oxidation potential, except for in the case of rr-P3HT with the large tetrakis[3,5-bis(trifluoromethyl)phenyl]borate anion. We propose that this large anion is excluded from the crystalline regions and thus the oxidation potential is similar to that of rra-P3HT. The anions also result in significant differences in polaron absorbance and ionization energies, thereby emphasizing the important role of the counterion in determining the optical and electronic properties of doped π-conjugated polymers.

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“…Generally, we can see effect of main chain composition and effect of side pendant groups. Polyphenylenes or polyfluorenes exhibit HOMO values −5.8 eV while in P33 the value is much closer to poly3‐alkylthiophenes due to the overwhelming effect of thiophene in main chain [35,36] …”

Section: Resultsmentioning

confidence: 99%

“…closer to poly3-alkylthiophenes due to the overwhelming effect of thiophene in main chain. [35,36] Second effect is the electron-withdrawing action of ester pendant group. Esters are not considered strong EWGs but every phenylene contains two of them.…”

Section: Cyclic Voltammetrymentioning

confidence: 99%

Thin Films of Thiophene Copolymer / Phenylated Fullerene: Fluorescence Dynamics, Surface Topography and Chemical Composition

et al. 2020

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System of thiophene‐based polymer (P33) donor and fullerene acceptor is studied for prospective applications in organic photovoltaics. The films of P33 and P33/PCBM are characterized by absorption, steady‐state and time‐resolved fluorescence, AFM, CV and SIMS. PCBM quenches fluorescence of the blend and results in blue shift from 524 nm to 505 nm, indicating the charge transfer. The global ultrafast fluorescence decay times τ1 for P33 and P33/PCBM are 8.9 ps and 3.8 ps, respectively, describing self‐trapped exciton relaxation. The topography of P33 and P33/PCBM was studied by AFM and fluorescence dynamics is correlated with surface topography. Scans of P33/PCBM with average roughness of 5.3 nm reveal flatter surface than P33. These results suggest that the flatter surface and also proposed flatter internal structure in more organized nano‐domains promote the faster fluorescence dynamics. The study of P33/PCBM blend film provides correlation between the dynamics and the structure.

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Measurements of HOMO-LUMO levels of poly(3-hexylthiophene) thin films by a simple electrochemical method

Cited by 36 publications

References 34 publications

Effects of Mechanical Stretching on the Properties of Conjugated Polymers: Case Study for MEH‐PPV and P3HT Oligomers

Effects of Mechanical Stretching on the Properties of Conjugated Polymers: Case Study for MEH‐PPV and P3HT Oligomers

Impact of the anion on electrochemically doped regioregular and regiorandom poly(3‐hexylthiophene)

Thin Films of Thiophene Copolymer / Phenylated Fullerene: Fluorescence Dynamics, Surface Topography and Chemical Composition

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