Transition-Metal Carbene Complexes with Blue Phosphorescence and Metal Assisted Delayed Fluorescence

Description

Organic light-emitting diodes (OLED) were extensively used in fabrication of both the flat-panel and flexible displays for all optoelectronic devices. Great color tunability, high efficiencies, and excellent versatility are their important advantages of OLED devices. From the material prospective, the emitters, carrier transporters and host materials are all critical for the ongoing developments, i.e., better materials give better device performances. As to the emitters, all RGB colors are required to attain full usages of OLED devices. However, amidst piles of blue fluorophores and thermally assisted delayed fluorescence (TADF) emitters, the stable blue phosphors remained to be underdeveloped and the demands unavoidably stirred the activities in both industrial and academic sectors. Hence, we turned to the carbene chelates di-N-aryl substituents in preparation of transition-metal based phosphors, particularly to those with blue luminescence. It is believed that our proposed carbene chelates will offer the greatest stability and shortened radiative lifetime, together with tunable emission wavelengths, to which the resulting phosphors are complimentary to the organic TADF emitters documented in literature. In this proposal, we intended to focus on the design and synthesis of the respective Ir(III), Pt(II) and Au(I) phosphors. They are expected to exhibit the true-blue and blue emission with shortened radiative lifetime to the microsecond and below and, ultimately, give rise to OLED devices with superior performances.