Efficient and long-life green light-emitting diodes comprising tridentate thiol capped quantum dots

In this paper, the green quantum dots capped with the ligand, tris(mercaptomethyl)nonane (TMMN), are fabricated as the light-emitting layer for efficient and bright light-emitting diodes. These TMMN-capped quantum dots exhibit well-preserved photoluminescence properties with quantum yields of approximate to 90% after ligand exchange. The light-emitting diodes based on TMMN-capped quantum dots are reported with a maximum external quantum efficiency of 16.5% corresponding to a power efficiency and current efficiency of 57.6 lm W-1 and 70.1 cd A(-1), respectively. The devices exhibit high color stability that is not markedly affected by the increase of applied voltage, thus leading to a high color reproducibility. Most importantly, the devices exhibit high environmental stability. For the highest luminance devices (with emitting layer thickness of 25 nm) and the highest power efficiency devices (with emitting layer thickness of 38 nm), the lifetimes are > 480 000 h and > 110 000 h, respectively.