Platinum-based metallomesogens bearing a Pt(4,6-dfppy)(acac) skeleton: Synthesis, photophysical properties and polarised phosphorescence application

Xuefeng Yang, Xiugang Wu, Di Zhou, Junting Yu, Guohua Xie, Duncan W. Bruce, Yafei Wang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Polarised phosphorescence has a bright future in backlighting for conventional liquid crystal displays due to its theoretical 100% internal quantum efficiency and low cost. However, there are scarce reports on polarised phosphorescence from metallomesogens. In this contribution, a platinum-based metallomesogen containing a mesogenic biphenyl (Pt1) was prepared and characterised. To further explore the effect of the substituent on mesophase and emission properties, a related complex Pt2 containing a tetraphenylethene (TPE) moiety was also synthesised. Both complexes melt at elevated temperatures but thereafter do not appear to crystallise on cooling. Complex Pt1 shows an enantiotropic nematic phase from which a broad emission can be seen when spread as a film; in solution, an intense, sky-blue emission is observed. For Pt2, which shows a monotropic SmA phase, the emission in the condensed phase is suppressed and there is only weak emission in solution. Polarisation-dependent photoluminescence with a polarised ratio of 5.4 was obtained for the aligned film of a Pt1:polyimide mixture. Using Pt1 as an emissive layer, non-doped, polarised organic light-emitting diodes presented a broad emission spectrum in the range of 450-900 nm with a polarised ratio of 1.33 and the highest external quantum efficiency of 1.1%. This research has an important significance for achieving broad-based polarised phosphorescence from platinum complex-based metallomesogens.

Original languageEnglish
Pages (from-to)13368-13377
Number of pages10
JournalDalton Transactions
Issue number38
Early online date30 Aug 2018
Publication statusE-pub ahead of print - 30 Aug 2018

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