Co-deposited copper(I) complexes integrating phosphorescence and TADF properties for highly efficient OLEDs.

The strategy to co-deposit copper halide and organic materials to directly generate emissive copper complexes is taken into account as a straightforward and promising way to fabricate organic light-emitting diodes (OLEDs) compared with using presynthesized complexes. In this work, four aza-9,9-Spirobifluorenes (aza-SBFs) with the nitrogen atom at different positions of azafluorene moiety were co-deposited with copper(I) iodide (CuI) to form emissive complexes. Intriguingly, we found that the emission properties of these co-deposited copper complexes contain phosphorescent and thermally activated delayed fluorescent (TADF) characteristics. Through changing the position of nitrogen atom, the TADF process can be effectively enhanced, resulting in PLQY up to 92.2 %. Consequently, green OLED with a high current efficiency of 41.9 cd/A, power efficiency of 32.9 lm/W, and external quantum efficiency (EQE) of 16.8 % were achieved by employing the co-deposited copper complex as the emitter. [Display omitted] • aza-9,9-Spirobifluorenes were co-deposited with CuI to form emissive complexes. • The generated materials possessed phosphorescence and TADF emission processes. • High PLQY up to 92.2 % was realized benefiting from the increased TADF proportions. • Green OLED with the EQE of 16.8 % and current efficiency of 41.9 cd/A was achieved. [ABSTRACT FROM AUTHOR]