Highly efficient white-emitting thermally activated delayed fluorescence polymers: Synthesis, non-doped white OLEDs and electroluminescent mechanism
Single white-emitting polymers are greatly desired to develop solution-processed white organic light-emitting diodes (WOLEDs) with simple fabrication processes and low-energy-consumption. Thermally activated delayed fluorescence (TADF) polymers harvesting both triplet and singlet excitons without he...
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Veröffentlicht in: | Nano energy 2019-11, Vol.65, p.104057, Article 104057 |
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Sprache: | eng |
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Zusammenfassung: | Single white-emitting polymers are greatly desired to develop solution-processed white organic light-emitting diodes (WOLEDs) with simple fabrication processes and low-energy-consumption. Thermally activated delayed fluorescence (TADF) polymers harvesting both triplet and singlet excitons without heavy metals are promising candidates for solution-processable white-emitting devices. However, all-TADF polymers with efficient white emissions have not been well-developed. Herein, a new strategy is proposed to develop a series of all-TADF single white-emitting polymers for highly efficient non-doped solution-processed WOLEDs. A WOLED based on one of these polymers as the emitting layer achieves an EQEmax of 14.2%, a CEmax of 38.8 cd A−1, and a PEmax of 20.3 lm W−1 with the CIE coordinates of (0.33, 0.42) and (0.31, 0.39) at 100 cd m−2 and 2000 cd m−2, respectively. The double-channel trap-assisted and Langevin recombinations account for broad recombination zones, reduced formation of high-energy excitons on hosts and enhanced efficiency of PDTPT-1, 2&3 based OLEDs. As far as it is known, PDTPT-1 is the highest efficient white-emitting TADF polymer so far.
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•A series of white-emitting polymers with obvious TADF feature are successfully synthesized.•These polymers exhibit dual-color white emission with deep-blue and yellow emission.•EQEmax of the nodoped single polymer OLEDs reaches to 14.2% with CIE of (0.33, 0.42).•Langevin recombination is one of the main recombination pathways in these OLEDs.•Trap-assisted recombination can be take into account for partial electroluminescent mechanism. |
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ISSN: | 2211-2855 |
DOI: | 10.1016/j.nanoen.2019.104057 |