Fabrication of aqueous quantum dot light-emitting diodes based on eco-friendly solvents

Abstract

Quantum dots are promising candidates as an emissive material in next-generation display. In fabricating such light-emitting devices, solution process has been developed for replacing conventional thermal evaporation due to low fabrication cost and potential applicability for flexible plastic substrates. Using eco-friendly solvents in the whole fabrication process is attractive in terms of environmental concerns such as waste liquid disposal. Herein, we fabricated quantum dot light-emitting diodes (QLEDs) of which layers are all based on eco-friendly solvents. The structure of fabricated QLEDs was ITO/PEDOT:PSS/poly(9-vinylcarbazole) (PVK)/QDs/ZnO/Al. All layers were sequentially deposited by simple and cost-effective spin-coating process except for Al electrode. To prepare all the layers in the devices from eco-friendly solvents, CdTe quantum dots were synthesized in aqueous media under open-air condition. Also, PVK nanoparticles and ZnO nanoparticles were synthesized and dispersed in ethanol. Thus, we successfully fabricated the QLEDs through eco-friendly solvent process and the fabricated devices emitting orange-light shows the turn-on voltage of 4.3 V.