English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/211180
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL | DATACITE
Exportar a otros formatos:


Transport and optical gaps in amorphous organic molecular materials

AuthorsSan-Fabián, Emilio; Louis, Enrique; Díaz-García, María A.; Chiappe, Guillermo; Vergés, José A.
KeywordsTransport gap
Optical gap
Organic light-emitting diode
Time-dependent DFT
Issue Date2019
PublisherMolecular Diversity Preservation International
CitationMolecules 24 (2019)
Abstract[EN] The standard procedure to identify the hole- or electron-acceptor character of amorphous organic materials used in OLEDs is to look at the values of a pair of basic parameters, namely, the ionization potential (IP) and the electron affinity (EA). Recently, using published experimental data, the present authors showed that only IP matters, i.e., materials with IP > 5.7 (<5.7) showing electron (hole) acceptor character. Only three materials fail to obey this rule. This work reports ab initio calculations of IP and EA of those materials plus two materials that behave according to that rule, following a route which describes the organic material by means of a single molecule embedded in a polarizable continuum medium (PCM) characterized by a dielectric constant ε. PCM allows to approximately describe the extended character of the system. This “compound” system was treated within density functional theory (DFT) using several combinations of the functional/basis set. In the preset work ε was derived by assuming Koopmans’ theorem to hold. Optimal ε values are in the range 4.4–5.0, close to what is expected for this material family. It was assumed that the optical gap corresponds to the excited state with a large oscillator strength among those with the lowest energies, calculated with time-dependent DFT. Calculated exciton energies were in the range 0.76–1.06 eV, and optical gaps varied from 3.37 up to 4.50 eV. The results are compared with experimental data.
Publisher version (URL)http://dx.doi.org/10.3390/molecules24030609
Identifiersdoi: 10.3390/molecules24030609
e-issn: 1420-3049
Appears in Collections:(ICMM) Artículos
Files in This Item:
File Description SizeFormat 
Verges_Transport_molecules-24-00609_2019.pdf2,25 MBAdobe PDFThumbnail
Show full item record
Review this work

WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.