Electric field-induced color switching of luminescence from ZnO nanoparticle/polymer nanostructure

We report on reversible switching induced by an electric field between blue-green and red cathodoluminescence (CL) in the ZnO:Mg nanoparticles/poly(4,4'-diphenylene diphenylvinylene) (PDPV) nanostructure. It has been found that PDPV-ZnO:Mg nanostructures shows the CL emission maximum in the blue-green region without an electric field. The positive bias voltage suppressed the blue-green emission and shifted the emission maximum to the red region. The mechanism for the formation of the exited states in PDPV-ZnO:Mg nanostructures is discussed. It implies the presence of radiative recombination channels, which can be adjusted by a biased voltage to the free carrier depletion or accumulation mode.