Solution-Processed Organic Light-Emitting Diodes of Yellow-Emitting PtAg2 Complexes with an External Quantum Efficiency of 21.7%

Yellow emission is a complementary color of blue for achieving white emission. Here, we report two yellow-emitting PtAg2 heterotrinuclear complexes (1 and 2) of 4-ethynyl-N,N-diphenylaniline, supported by bis­(diphenylphosphinomethyl)­phenylphosphine (dpmp) and bis­(di-o-tolylphosphinomethyl)­phenylphosphine (dTolmp), respectively. The solution-processed organic light-emitting diode based on complex 1 exhibits yellow emission peaked at 567 nm with the highest current efficiency (CE) of 49.7 cd A–1 and an external quantum efficiency (EQE) of 14.3%. Remarkably, the device performance of complex 2 containing dTolmp with a larger steric hindrance as the supporting ligand is dramatically enhanced with the CE boosting to 69.1 cd A–1 and EQE of 21.7% and, more importantly, a better color saturation of yellow emission peaked at 579 nm with the CIE of (0.49, 0.50).