Efficient tandem organic light-emitting diode with fluorinated hexaazatrinaphthylene charge generation layer

We present the fluorinated hexaazatrinaphthylene derivative, 1,2,3,4,7,8,9,10,13,14,15,16-dodecafluoro-5,6,11,12,17,18-hexaazatrinaphthylene (HATNA-F12), as a new material to replace another hexaazatrinaphthylene molecule, 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN), which is widely used as an intermediate connector and charge generation layer (CGL) in tandem organic light-emitting diodes (OLEDs). Upon comparison with the reference single emitting layer unit OLED, the tandem device with HATNA-F12 CGL had improved current efficiency and external quantum efficiency of 42.1% and 41.7%, respectively. Our results show that HATNA-F12 is an excellent substitute for HAT-CN and has more promising characteristics as a CGL material for applications in tandem OLEDs. When compared to devices with HAT-CN CGL, the green tandem OLEDs with CGL consisting of HATNA-F12 demonstrated improved current efficiency, power efficacy, and external quantum efficiency values, while the change of the CGL material had almost no effect on the operating voltage, current density, and color coordinates of the OLEDs. We confirm that using the newly suggested HATNA-F12 molecule as a CGL in these OLEDs can enhance device efficiency.