Isopropanol solvent-treated MoS2 nanosheets from liquid phase exfoliation and their applications to solution-processed anode buffer layer of organic light-emitting diode

Solution-processed molybdenum disulfide (MoS2) nanosheets are facilely synthesized through liquid phase exfoliation and dispersed in isopropanol using a simple solvent exchange method. Raman spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy measurements show that the synthesized MoS2 nanosheets consist of typical two layers with superior film morphology and unique electronic properties such as partial oxidization and suitable surface work function. Effective anode buffer layers (ABLs) are obtained by spin-coating isopropanol-dispersed MoS2 nanosheets and accordingly efficient organic light-emitting diodes (OLEDs) are demonstrated. With tris(8-hydroxy-quinolinato)aluminium as emitter and 0.7 mg/mL MoS2 as ABL, the OLED shows a maximum luminous efficiency of 7.27 cd/A with an increment of 28.4% in comparison with the counterpart using favorite poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) as ABL. The current–voltage characteristics of hole-only devices confirm that solution-processed MoS2 nanosheets exhibit appropriate hole injection capacity, which favorably contributes to carrier balance and superb OLED performance. Our results open up an alternative route for accelerating MoS2 applications with solution process.