Fluoro substitution effect on 2,1,3-benzothiadiazole-based hybridized local and charge transfer state fluorophores for high-performance organic light-emitting diodesShow others and affiliations
2023 (English)In: Dyes and pigments, ISSN 0143-7208, E-ISSN 1873-3743, Vol. 213, article id 111184Article in journal (Refereed) Published
Abstract [en]
Fluoro substitution of organic semiconductors is an effective way to improve some related performance of the materials, such as the carrier mobility in organic photovoltaics (OPVs) and organic field-effect transistors (OFETs) applications. However, the influence of fluoro substitution for fluorophores in organic light-emitting diodes (OLEDs) applications is rarely reported. Here, with fluorinated electron-deficient 2,1,3-benzothiadiazole (BT) unit as the acceptor and triphenylamine (TPA) as the donor, we construct two new D-A-type fluorophores DTPA-fBT and DTPA-ffBT. Theoretical calculations and experimental results reveal that the lowest excited states (S1) of the materials are characterized by hybridized local and charge-transfer (HLCT) properties, in which the fluorine substitution will increase the proportion of the charge-transfer (CT) component. Due to the introduction of fluoro substitution, multiple fluorine hydrogen bonds are formed, which endow the molecules with more rigid conformation, leading to lower non-radiative rates and higher photoluminescence quantum yield (PLQY) in solution and doped film, as well as improved thermal stability in the solid state. As a result, the two fluorinated DTPA-ffBT demonstrate significantly improved performance in OLEDs with a maximum external quantum efficiency (EQE) of 7.25% (5.90% for fluorine-free counterpart) and very low-efficiency roll-off (roll-off <7% at 10,000 cd m-2).
Place, publisher, year, edition, pages
ELSEVIER SCI LTD , 2023. Vol. 213, article id 111184
Keywords [en]
Organic light -emitting diodes; Hybridized local and charge -transfer; Fluoro substitution; Low efficiency roll -off
National Category
Theoretical Chemistry
Identifiers
URN: urn:nbn:se:liu:diva-192934DOI: 10.1016/j.dyepig.2023.111184ISI: 000950053300001OAI: oai:DiVA.org:liu-192934DiVA, id: diva2:1749757
Note
Funding Agencies|National Key R & D Program of China [2020YFA0714604]; Natural Science Foundation of China [52103212, U20A6002]; Guangdong Basic and Applied Basic Research Foundation [2020A1515110738]; Basic and Applied Basic Research Major Pro- gram of Guangdong Province [2019B030302007]; Research and Development Funds for Science and Technology Program of Guangzhou [202007020004]; Natural Science Foundation of Guangdong Prov- ince [2019B121205002]; Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates [2019B030301003]
2023-04-112023-04-112023-04-11