Experimental and Theoretical Investigation into the Polaron Structure of K-Doped Polyfluorene Films
| Autor: | Sarbani Ghosh, Xianjie Liu, Yongzhen Chen, Igor Zozoulenko, Mats Fahlman, Slawomir Braun |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Physics::Optics 02 engineering and technology Electronic structure 010402 general chemistry Polaron 01 natural sciences Condensed Matter::Materials Science Polyfluorene chemistry.chemical_compound X-ray photoelectron spectroscopy Condensed Matter::Superconductivity Physical and Theoretical Chemistry Absorption (electromagnetic radiation) Optical transition Doping Condensed Matter Physics 021001 nanoscience & nanotechnology 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials General Energy chemistry Physical chemistry 0210 nano-technology Den kondenserade materiens fysik |
| Zdroj: | The Journal of Physical Chemistry C. 125:937-945 |
| ISSN: | 1932-7455 1932-7447 |
| DOI: | 10.1021/acs.jpcc.0c08442 |
| Popis: | The evolution of the electronic structure and optical transition upon n-doping of poly(9,9-dioctylfluorene) (PFO) films is elucidated with photoelectron spectroscopy, optical absorption, density functional theory (DFT), and time-dependent DFT (TD-DFT) calculations. Optical absorption measurements extending into near infrared show two low-energy absorption features at low doping ratios and an additional peak at a higher energy of similar to 2.2 eV that disappears with increasing doping ratios. A gap state (i.e., polaronic state) close to the Fermi level and a significantly destabilized highest valence band appear in the experimentally measured ultraviolet photoelectron spectra. These experimental results are interpreted by the TD-DFT calculations, which show that the lower energy peaks originate from the excitation from polaronic states to the conduction band, while the higher energy peak mainly originates from the destabilized valence band to conduction band transitions and only appears at low doping ratios (c(red) Funding Agencies|Knut and Alice Wallenberg Foundation project "Tail of the Sun"; Swedish Foundation for Strategic ResearchSwedish Foundation for Strategic Research [SE13-0060]; Swedish Research CouncilSwedish Research CouncilEuropean Commission [2016-05498, 2016-05990]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971] |
| Databáze: | OpenAIRE |
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