High-brightness perovskite quantum dot light-emitting devices using inkjet printing

The performance of perovskite quantum dot light-emitting diodes (PeQLEDs) has been rapidly enhanced recently, but the devices are still stuck in the stage of using small-scale solution processes, such as spin-coating. In this work, we report the realization of high performance PeQLEDs by using inkjet printing technique. We demonstrate the preparation of a printable perovskite quantum dot ink by using a hybrid solvent consisting of high boiling solvent dodecane and low boiling solvent n-octane. A universal strategy for eliminating coffee rings during inkjet printing of perovskite inks is developed based on the modulation of ink formulation, and the stacking model of perovskite quantum dot in a pixel pit structure is proposed. The inkjet-printed PeLEDs exhibit a low turn-on voltage of 2.7 V, a brightness of 10992 cd/m2 at 6.6 V and a maximum current efficiency of 8.67 cd/ A, which is by far the highest value reported for inkjet-printed PeLEDs. The results pave a way for future realization of high performance pixelated PeLED displays with inkjet printing technique.