Synthesis of Highly Monodisperse Cu_2O Nanocrystals and Their Applications as Hole-Transporting Layers in Solution-Processed Light-Emitting Diodes

摘要

The synthesis of phase-pure, narrow-size-distributed and highly stable Cu_2O nanocrystals is reported, which can be processed as hole-transporting layers (HTLs) in solution-processed optoelectronic devices. The synthesis is based on a thermal decomposition process with a ligand protection strategy. The reactivity of precursor can be tuned by simply modulating the concentration of oleylamine in non-coordinated solvent, resulting in effectively controlling the size and size distribution of Cu_2O nanocrystals. Combined with ligand protection strategy of using lithium stearate and moderate reaction temperature of 170 °C, in situ aggregation of Cu_2O nanocrystals could be inhibited, exhibiting excellent stability in hexane for several months. The resulting phase-pure colloidal Cu_2O particles (after ozone-treatment) were applied as HTLs in polymer light-emitting diodes, the performance of which are comparable to that of the poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) based devices.