Cathode made by silver-precursor ink for all-solution processed quantum dots light-emitting diodes

Abstract

To realize all-solution processed quantum dots (QDs) light-emitting didoes (QLEDs) with every functional layer processed via wet coating, silver-precursor ink converted cathode is introduced for the first time. One challenge to utilize solution-processed cathode is that the silver-precursor ink reacts with the electron transport layer zinc oxide (ZnO). Another one is that the silver ions permeate through ZnO to quench the QDs' fluorescence. To overcome the challenges, the annealing temperature of ZnO is optimized to 180 °C, while the silver-precursor ink's annealing condition of 180 °C/5 min is selected. As a result, the all-solution processed QLEDs achieve a maximum brightness of 1.32 × 10 4 cd m −2 , a maximum current efficiency of 8.98 cd A −1 , and a maximum external quantum efficiency of 6.92% which reaches 61% of the efficiency of QLEDs with evaporated silver cathode. - Cathode is made by silver-precursor ink to realize all-solution processed QLEDs. - ZnO is annealed at 180 °C to enhance the corrosion resistance. - ZnO can't fully prevents silver ions' permeation from quenching fluorescence. - Silver-precursor ink is converted to silver at high temperature with short time. - Efficiency with solution cathode reach 61% of that with evaporated cathode.