Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/102153
Title: Design Strategy for Ag(I)-Based Thermally Activated Delayed Fluorescence Reaching an Efficiency Breakthrough
Authors: Shafikov, M. Z.
Suleymanova, A. F.
Czerwieniec, R.
Yersin, H.
Issue Date: 2017
Publisher: American Chemical Society
Citation: Design Strategy for Ag(I)-Based Thermally Activated Delayed Fluorescence Reaching an Efficiency Breakthrough / M. Z. Shafikov, A. F. Suleymanova, R. Czerwieniec, et al. — DOI 10.1021/acs.chemmater.6b05175 // Chemistry of Materials. — 2017. — Vol. 29. — Iss. 4. — P. 1708-1715.
Abstract: A design strategy for the development of Ag(I)-based materials for thermally activated delayed fluorescence (TADF) is presented. Although Ag(I) complexes usually do not show TADF, the designed material, Ag(dbp)(P2-nCB) [dbp = 2,9-di-n-butyl-1,10-phenanthroline, and P2-nCB = nido-carborane-bis(diphenylphosphine)], shows a TADF efficiency breakthrough exhibiting an emission decay time of τ(TADF) = 1.4 μs at a quantum yield of ΦPL = 100%. This is a consequence of three optimized parameters. (i) The strongly electron-donating negatively charged P2-nCB ligand destabilizes the 4d orbitals and leads to low-lying charge (CT) states of MLL′CT character, with L and L′ being the two different ligands, thus giving a small energy separation between the lowest singlet S1 and triplet T1 state of ΔE(S1-T1) = 650 cm-1 (80 meV). (ii) The allowedness of the S1 → S0 transition is more than 1 order of magnitude higher than those found for other TADF metal complexes, as shown experimentally and by time-dependent density functional theory calculations. Both parameters favor a short TADF decay time. (iii) The high quantum efficiency is dominantly related to the rigid molecular structure of Ag(dbp)(P2-nCB), resulting from the design strategy of introducing n-butyl substitutions at positions 2 and 9 of phenanthroline that sterically interact with the phenyl groups of the P2-nCB ligand. In particular, the shortest TADF decay time of τ(TADF) = 1.4 μs at a ΦPL value of 100%, reported so far, suggests the use of this outstanding material for organic light-emitting diodes (OLEDs). Importantly, the emission of Ag(dbp)(P2-nCB) is not subject to concentration quenching. Therefore, it may be applied even as a 100% emission layer. © 2017 American Chemical Society.
Keywords: DECAY (ORGANIC)
DENSITY FUNCTIONAL THEORY
FLUORESCENCE
LIGANDS
LIGHT EMITTING DIODES
METAL COMPLEXES
ORGANIC LIGHT EMITTING DIODES (OLED)
CONCENTRATION QUENCHING
HIGH QUANTUM EFFICIENCY
NEGATIVELY CHARGED
OPTIMIZED PARAMETER
ORGANIC LIGHT EMITTING DIODES(OLEDS)
RIGID MOLECULAR STRUCTURE
THERMALLY ACTIVATED DELAYED FLUORESCENCES
TIME DEPENDENT DENSITY FUNCTIONAL THEORY CALCULATIONS
QUANTUM EFFICIENCY
URI: http://hdl.handle.net/10995/102153
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85013996059
PURE ID: 1612190
5a443796-955b-41d0-ad47-d6080fa2d583
ISSN: 8974756
DOI: 10.1021/acs.chemmater.6b05175
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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