Organic-Phase Synthesis of Blue Emission Copper Nanoparticles for Light-Emitting Diodes

Copper nanoparticles (Cu NPs) are affordable, heavy metal-free materials with tunable emission wavelength, which could provide versatile applications in the fields of catalysis, photoluminescence, and biomedicine. In contrast to conventional Cu NPs in the aqueous phase, organic-phase Cu NPs with enhanced emission properties are needed to expand the range of applications in optoelectronic devices. Herein, organic-soluble Cu NPs were synthesized for the first time by reducing Cu2+ to Cu NPs using tris(dimethylamino)phosphine [(DMA)3P] as the reducing agent. The quantum yield (QY) of the synthesized Cu NPs was further enhanced to 32% by introducing a In3+ cation to passivate the surface defects. Due to the orthogonal ligand of Cu NPs without interfering with other layers in light-emitting diodes (LEDs), the first blue Cu NP LED with an external quantum efficiency (EQE) of 0.14% was achieved.