Samsung Display has developed a 18.2" 2560x1440 202 PPI inkjet-printed OLED display, that features the highest current efficiency of any inkjet-printed OLED, with the brightness at 350 cd/m2 (full white).

Samsung Display 18.2'' ink-jet printed OLED (SID DW 2020)

Samsung Display says that the high brightness was achieved by tuning the top-emission device structure with high performance soluble materials. The high pixel resolution was achieved by modulating the jetting waveform for ejecting ink drops and improving the drop placement accuracy by selecting the right ink formulations in terms of viscosities and surface energies.

Samsung says that the performance of soluble materials lags quite significantly behind that of vacuum deposited materials. Blue soluble OLED emitters are about 66 less efficiency compared to evaporable ones, for example. Improving the performance of soluble blue OLED emitters will be key to achieve commerciability in inkjet printed OLED displays.

Blue OLED evaporation vs ink-jet material performance (SDC, SID DW 2020)

Atomic Force Microscopy for next-gen OLED processesAtomic Force Microscopy for next-gen OLED processes