Organic Electroluminescence of ZnSe/ZnS Nanocrystal Hybrid with MEH-PPV

Core-shell structure ZnSe/ZnS nanocrystal(NCs) with size of about 4 nm was synthesized in aqueous solution,Good cubic crystal with zinc-blend structure of ZnSe/ZnS NCs was confirmed by using X-ray diffraction(XRD) and transmission electron microscopy(TEM) technology.A surfactant was replaced of ZnSe/ZnS NCs to transfer from aqueous solution to organic solution,which have been great dispersed in organic polymer.Organic light emitting devices were fabricated using a thin film which was spin-coated the MEH-PPV and ZnSe/ZnS NCs mixer solution under the quality ratio of 1∶0.5 as the emitting layer.The electroluminescence(EL) diodes with single-layer structure of ITO/poly [2-methoxy-5-(2′-ethyl hexyloxy-p-phenylenevinylene)](MEH-PPV)∶ZnSe/ZnS(50 nm)/Al and a multilayer structure of ITO/poly(ethylene-dioxythio phene)∶poly(styrenesulfonate)(PEDOT∶PSS)(70 nm)/MEH-PPV∶ZnSe(ZnS)(50 nm)/bathocuproine(BCP)(15 nm)/tris-(8-hydroxylquinoline)-aluminum(Alq3)(12 nm)/LiF(0.5 nm)/Al were fabricated,respectively.The clearly blue shift of the emissive peak in the multilayer device was measured with the increasing of applied voltage,but there is not the changing of the emissive peak in the single-layer device.Under the effect of applied voltage and the hole blocking layer BCP,EL of multilayer device may be from MEH-PPV and ZnSe/ZnS NCs.